Crystal Structure, Magnetism, and Electronic Properties of a Rare-Earth-Free Ferromagnet: MnPt5As

Article abstract of DOI:10.1021/acs.chemmater.0c00244

The design and synthesis of targeted functional materials have been long-term goals for materials scientists. Although a universal design strategy is difficult to generate for all types of materials, it is still helpful for individual families of materials to have such design rules. Herein, we incorporated several significant chemical and physical factors relevant to magnetism, such as structure-type, atomic distance, and spin-orbit coupling, and have thereby successfully synthesized a new rare-earth-free ferromagnet, MnPt₅As, for the first time. MnPt₅As can be prepared by high-temperature pellet methods. According to the X-ray diffraction results, MnPt₅As crystallizes in a tetragonal unit cell with the space group P4/mmm (Pearson symbol tP7). Magnetic measurements on MnPt₅As confirm ferromagnetism in this phase with a Curie temperature of ～301 K and a saturated moment of 3.5 μ_B per formula unit. Evaluation by applying the Stoner criterion also indicates that MnPt₅As is susceptible to ferromagnetism. Electronic structure calculations using the WIEN2k program with local spin density approximation imply that the spontaneous magnetization of this phase arises primarily from the hybridization of the d orbitals on both Mn and Pt atoms. The theoretical assessments are consistent with the experimental results. Moreover, spin-orbit coupling effects heavily influence the magnetic moments in MnPt₅As. MnPt₅As is the first ferromagnetic material in the MgPt₅As structure-type. The discovery of MnPt₅As offers a platform to study the interplay between magnetism and structure.

Full text of DOI:10.1021/acs.chemmater.0c00244

Subscriber access provided by UNIV OF NEW ENGLAND ARMIDALE
Article
Crystal Structure, Magnetism, and Electronic
5
Properties of a Rare-Earth-Free Ferromagnet: MnPtAs
Xin Gui, and Weiwei Xie
Chem. Mater., Just Accepted Manuscript • DOI: 10.1021/acs.chemmater.0c00244 • Publication Date (Web): 24 Apr 2020
Downloaded from pubs.acs.org on April 24, 2020
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
Crystal Structure, Magnetism, and Electronic Properties of a Rare-Earth-
Free Ferromagnet: MnPt As
5
Xin Gui, Weiwei Xie*
Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
ABSTRACT
The design and synthesis of targeted functional materials have been long-term goals for
materials scientists. Although a universal design strategy is difficult to generate for all types of
materials, it is still helpful for individual families of materials to have such design rules. Herein,
we incorporated several significant chemical and physical factors relevant to magnetism, such as
structure type, atomic distance, and spin-orbit coupling, and have thereby successfully synthesized
a new rare-earth-free ferromagnet, MnPt As, for the first time. MnPt As can be prepared by using
5
5
high-temperature pellet methods. According to X-ray diffraction results, MnPt As crystallizes in
5
a tetragonal unit cell with the space group P4/mmm (Pearson symbol tP7). Magnetic measurements
on MnPt As confirm ferromagnetism in this phase with a Curie temperature of 301 K and a
5
saturated moment of 3.5  per formula unit. Evaluation by applying the Stoner Criterion also
B
indicates that MnPt As is susceptible to ferromagnetism. Electronic structure calculations using
5
the WIEN2k program with local spin density approximation imply that the spontaneous
magnetization of this phase arises primarily from the hybridization of the d orbitals on both Mn
and Pt atoms. The theoretical assessments are consistent with the experimental results. Moreover,
spin-orbit coupling effects heavily influence the magnetic moments in MnPt As. MnPt As is the
5
5
first ferromagnetic material in the MgPt As structure type. The discovery of MnPt As offers a
5
5
platform to study the interplay between magnetism and structure.
ACS Paragon Plus Environment

Chemistry of Materials
Page 2 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Introduction
How one can easily approach new ferromagnetic materials (e.g. create a practical design
strategy), especially to induce high transition temperatures and high saturated moments, is a
demanding necessity for materials synthetic materials scientists. Meanwhile, the exploration of
ferromagnetic intermetallic materials without strategically vulnerable rare-earth elements is
critical for information technology applications, such as magnetic and magnetoelastic sensors,1
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
3–5
6
hard-disk drives, spintronics,
and biomedical devices. Most research focuses on using
magnetically active 3d transition metals such as Fe, and Co to replace rare-earth elements.7–10
Some of the 3d elements are ferromagnetically ordered above room temperature (e.g. Fe, Co, Ni).11
When alloyed with other elements, the magnetic and mechanic properties can be tuned
accordingly.12,13 AlNiCo-type magnetic systems, for example have attracted attention for their
temperature stability and mechanical properties. AlNiCo has a relatively large coercivity primarily
due to the shape anisotropy of nano-sized particles rather than the magneto-crystalline
anisotropythat is typical for rare-earth based magnets.14–18 Later, quite a few Mn-based alloys were
discovered to exhibit ferromagnetism, including Mn-B, Mn-Ga, Mn-Ge, Mn-Sb and Mn-As.19
Particularly, Mn-Al20–26 and hexagonal NiAs-type Mn-Bi alloys27–32 have potential due to their
large magnetic crystalline anisotropy.
Mn-Mn distances significantly affect how magnetic moments are ordered in some systems,
3
3-35
such as RMn Ge and RMn Ge (R = heavy-lanthanide elements or Y).
Moreover, the
2
2
6
6
distribution patterns of Mn atoms in AMnX-based compounds (A = Li, Ni, Cu or La; X = As or
3
6
Sb) are similar and are also related to the saturated moment per Mn atom. In such systems,
ferromagnetic ordering and high saturated magnetic moments are usually preferred for longer Mn-
Mn distances while shorter Mn-Mn distances favor antiferromagnetic interactions. With this
intriguing feature of Mn atom geometries, our candidate system is the tetragonal MgPt As-type
5
structure, which can be considered as an anti-type structure of one of the most well-known heavy
3
7
fermion superconductors, CeCoIn . Among all four atomic sites in the MgPt As-type structure,
5
5
if an Mn atom can be placed onto the Mg site, the neighboring Mn-Mn distance can reach over 4
Å, due to the periodicity of the unit cells and the change of atomic radii, which is comparable to
5
2
the ferromagnetic cases in ref. 36. Furthermore, with the electronic configuration of [Ar]3d 4s ,
Mn is well-known to provide high magnetic moments in intermetallics. The spin-orbit coupling
ACS Paragon Plus Environment

Page 3 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
(
SOC) effect is another crucial factor when designing new magnetic materials due to its ability to
3
8
interact with the spin-polarization (magnetism) of the material. For example, a strong SOC effect
can enhance magnetocrystalline anisotropy, which is important for high coercivities and energy
products in ferromagnets, such as FePt39,40. Heavy elements with 4d/5d or 5p/6p block electron
orbital occupancy, platinum and bismuth for example, are normally considered to be the source of
strong SOC effects.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
With these design rules in mind, we successfully designed and synthesized a new rare-
earth-free ferromagnetic intermetallic compound MnPt As. Magnetic property measurements and
5
theoretical calculations both show consistently that MnPt As favors ferromagnetic ordering with
5
a saturated moment ~ 3.5  per formula. The magnetic moment in MnPt As is theoretically
B
5
proved to be strongly related to the atomic interaction between Mn and its neighboring Pt atoms.
Meanwhile, MnPt As is the first high-T magnetic material in this structure type. The discovery of
5
c
MnPt As paves a way to more remarkable magnetic compounds with similar structures.
5
ACS Paragon Plus Environment

Chemistry of Materials
Page 4 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Experimental Section
Preparation of Polycrystalline MnPt As: Polycrystalline MnPt As was synthesized by the high-
5
5
temperature solid-state method. Mn powder, Pt powder, and As powder were evenly mixed and
4
1
pelletized in an argon-filled glovebox due to the toxicity of arsenic. The obtained pellet was
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-
5
placed in an alumina crucible and sealed into an evacuated silica tube (<10 torr). The sample was
o
o
heated up to 1050 C at a rate of 30 C per hour and held for 2 days, followed by cooling to room
temperature in 5 days. The polycrystalline product is air and moisture stable.
Phase Identification: The phase purity was determined by powder X-ray diffraction (PXRD)
conducted on a Rigaku MiniFlex 600 powder X-ray diffractometer with Cu K radiation ( =

o
o
o
1
.5406 Å, Ge monochromator). The Bragg angle measured was from 5 to 90 at a rate of 0.1 /min
o
with a step of 0.005 . Rietveld fitting in Fullprof was employed to obtain the weight percentage of
the major phase MnPt As.42
5
Structure Determination: The crystal structure of MnPt As was determined by single crystal X-
5
3
ray diffraction (SC-XRD). Multiple pieces of small crystals (~20×40×40 m ) were picked and
measured by a Bruker Apex II diffractometer equipped with Mo radiation ( = 0.71073 Å) at
K
room temperature. The small crystals were mounted on a Kapton loop with glycerol. Four different
crystal orientations were chosen to take the measurements with an exposure time of 10 seconds
per frame. The scanning 2 width was set to 0.5. Direct methods and full-matrix least-squares on
2
43
F within the SHELXTL package were applied to solve the structure. Data acquisition was
obtained via Bruker SMART software with the corrections of Lorentz and polarization effects done
by the SAINT program. Numerical absorption corrections were accomplished with XPREP.44,45
Scanning Electron Microscope (SEM): The crystal picture was taken using a high vacuum
scanning electron microscope (SEM) (JSM-6610 LV). Samples were placed on carbon tape prior
to loading into the SEM chamber and were examined at 20 kV.
Physical Properties Measurements: The Quantum Design Dynacool Physical Property
Measurement System (PPMS) was used to measure the magnetic property and resistivity with the
temperature range from 1.8 to 300 K with and without applied fields. The magnetic susceptibility
is defined as χ = M/H. Here, M is the magnetization in units of emu, and H is the applied magnetic
field. A standard relaxation calorimetry method was used to measure heat capacity and the data
ACS Paragon Plus Environment

Page 5 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
were collected in zero magnetic field between 220 K and 320 K using Apezon H-type grease. All
the measurements were performed on polycrystalline samples manually selected from MnPt As.
5
Electronic Structure Calculations: The electronic and ferromagnetic structures were calculated
using the Tight-Binding, Linear Muffin-Tin Orbital-Atomic Spheres Approximation (TB-LMTO-
ASA) with local (spin) density approximation (L(S)DA) method.46–48 Empty spheres are required
during the calculation, with the overlap of Wigner–Seitz (WS) spheres limited to smaller than
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
6%. A mesh of 9×9×6 k-points in the first Brillouin zone (BZ) was used to perform the detailed
calculations and obtain the density of states (DOS) and Crystal Orbital Hamiltonian Population
COHP) curves. The band structure, Fermi surfaces, and density of states (DOS) of MnPt As were
(
5
also calculated using the WIEN2k program, which has the full-potential linearized augmented
plane wave method (FP-LAPW) with local orbitals implemented.49,50 The electron exchange-
correlation potential was used to treat the electron correlation within the generalized gradient
5
1
approximation, which is parameterized by Perdew et. al. The conjugate gradient algorithm was
applied, and the energy cutoff was set at 500 eV. Reciprocal space integrations were completed
5
2
over an 8×8×4 Monkhorst-Pack k-points mesh. With these settings, the calculated total energy
converged to less than 0.1 meV per atom. The spin-orbit coupling (SOC) effects were only applied
for Pt atoms. The structural lattice parameters obtained from experiments were used for both
calculations.
ACS Paragon Plus Environment

Chemistry of Materials
Page 6 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Results and Discussion
Crystal Structure and Phase Determination of New Phase MnPt As: To obtain the structural
5
feature of the new phase, a single crystal of MnPt As was investigated. The refined results,
5
crystallographic data and anisotropic displacement parameters are shown in Tables 1, 2 and 3.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
MnPt As crystallizes in a tetragonal structure with the space group P4/mmm (No. 123). Mn located
5
at 1c (C symmetry), Pt atoms are on 1a (C symmetry) and 4i (C symmetry) sites, and the As
4
4
2
atom occupies 1b (C symmetry) sites. Partial occupancy refinements were tested, and no vacancy
4
or atomic mixture was discovered. A typical layered character can be observed for the structure,
where the face-shared Mn@Pt polyhedra layers are intercalated by As layers, as shown in FIG.
1
2
1
a. The distances between the two nearest Mn atoms are 3.931 (1) Å within the ab-plane and 7.092
(1) Å along the c-axis. The lattice parameters of MnPt As are 0.5% and 2.9% larger in a and c,
5
respectively, than those in MgPt As. The increased lattice parameters in MnPt As result in
5
5
increasing the bond length of Pt1-Pt1 along the c-axis from 2.756 Å in MgPt As to 3.129 Å in
5
MnPt As. However, the Mn-Pt distance is ~2.79 Å while the Mg-Pt distance is ~2.84 Å. The
5
2+
3+
shorter atomic Mn-Pt distance indicates the Mg in MgPt As can be replaced by the smaller Mn .
5
Moreover, we have identified a close relationship between the MnPt As type structure and
5
unconventional superconductor, PuCoGa . Pu-centered Ga cuboctahedra (Pu@Ga ) and Co-
5
12
centered Ga cubes (Co@Ga ) in PuCoGa can be analogies to Mn@Pt and As@Pt in MnPt As,
8
5
12
8
5
respectively.
ACS Paragon Plus Environment

Page 7 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FIG. 1 (a) Crystal structure of MnPt As determined by single crystal XRD where purple, grey and
5
orange balls stand for Mn, Pt and As atoms, respectively. Crystal picture showing a layered
o
o
character is on the right. (b) Rietveld fitting of PXRD pattern from 5 to 90 including contributions
from MnPt As, PtAs and Pt phases.
5
2
By fitting the PXRD pattern shown in FIG. 1b with the crystal structure obtained from SC-XRD,
it can be realized that the majority of the product is MnPt As (83.5(1) wt%) while there are two
5
non-magnetic impurity phases identified as PtAs (10.6(3) wt%) and Pt (5.9(1) wt%). The fitting
2
2
parameters of MnPt As phase are  = 3.62, R = 8.99, R = 12.0 and R = 6.32 and the difference
5
p
wp
exp
between the observed and calculated patterns is acceptable.No obvious extra phases could be found.
5
3
We tried to include a the fourth phase, MnAs , as possible magnetic impurity but it showed an
unreliable result due to the high R factor. Re-grinding the obtained polycrystalline samples and
reannealing were not helpful to make the product purer. Instead, multiple annealing steps lower
the degree of crystallization. The observed intensity of the PXRD pattern in such cases was
extremely low and most of the minor peaks cannot be identified.
ACS Paragon Plus Environment

Chemistry of Materials
Page 8 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FIG. 2. Temperature-dependence of magnetic susceptibility (Empty Circles) and inverse magnetic
susceptibility (Solid Circles) of MnPt As with ZFC (Red) and FC (Blue) methods. Green and cyan
5
lines indicate Curie-Weiss fitting lines for FC and ZFC curves, respectively.
Magnetic Susceptibility of Polycrystalline MnPt As: To investigate the magnetic properties of
5
MnPt As, polycrystalline samples of MnPt As were measured with an external magnetic field of
5
5
1
000 Oe. The results of both field-cooled (FC) and zero-field cooled (ZFC) M vs T are shown in
FIG. 2. On cooling down the sample, a dramatic increase of magnetic susceptibility is clearly
observed near Tc ~ 300 K which implies ferromagnetic ordering. An analysis of the inverse
susceptibility using Curie-Weiss (CW) law was modeled using  = C/(T- ), where  is the
CW
magnetic susceptibility, C is the Curie constant, and CW is the Curie-Weiss temperature. The
effective moments  fitted in the high temperature range (325 K- 345K) ( = 8C  ) are 3.56
eff
eff
B
(3)  for the FC method and 3.45 (3)  for the ZFC method, respectively. The fitted Curie-Weiss
B
B
temperatures for both methods are 301 (3) K (FC) and 305 (3) K (ZFC), which is consistent with
the ferromagnetic transition. The measurements were conducted on different specimens to confirm
the reproducibility.
ACS Paragon Plus Environment

Page 9 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FIG. 3. (a). Hysteresis loop from -9 T to 9 T under various temperatures from 1.8 K to 350 K. (b).
magnetization per Mn atom as a function of inverse magnetic field (1/ H) where the intercept of
0
each line with linear fitting indicates the saturated magnetic moment under that temperature.
Field-Dependent Magnetization in MnPt As: The hysteresis loops of magnetization M(H)
5
measured with applied fields up to 90 kOe at various temperatures from 1.8 K to 350 K are shown
in FIG. 3. The small coercivity (~15 Oe at 1.8 K) confirms the soft ferromagnetic character of
MnPt As. FIG. 3a shows the field dependences of the magnetization per Mn atom. MnPt As is
5
5
magnetized to saturate at M ~3.541 (1)  /Mn by an external magnetic field of ~0.7 T at 1.8 K.
s
B
On increasing temperature, the saturated moments decrease until 300 K and varnishes 350 K. In
particular, the field dependences of M(H) at 350 K investigated carefully upon both sweeping up
and down of the applied field shows paramagnetic properties. The exact saturated moments at
different temperatures are determined from the intercepts in FIG. 3b by linear fitting each line. The
results are consistent with the magnetic susceptibility measurements. The saturated moment
observed for MnPt As is smaller than what was reported for one of the most well-known Mn-based
5
5
4
ferromagnets, MnBi, where a saturated moment of ~4.2  /Mn can be found . The difference of
B
M between MnBi and MnPt As might be coming from the larger Mn-Mn distance and weaker
s
5
Mn-Mn magnetic interactions in MnPt As (d
~ 3.91Å in MnPt As; d
~ 3.05Å in MnBi).
5
Mn-Mn
5
Mn-Mn
Resistivity of MnPt As: To study the electronic properties of MnPt As, the resistivity of a small
5
5
single crystal of MnPt As was picked up and measured using the 4-probe method. FIG. 4 illustrates
5
the temperature-dependence of resistivity without an applied magnetic field. The resistivity
measurement shows the metallic properties of MnPt As. An anomaly can be observed around 300
5
ACS Paragon Plus Environment

Chemistry of Materials
Page 10 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
K which reflects the ferromagnetic ordering transition, similar with other ferromagnetic
intermetallics, for example, Ce CoGe , Ce Co Ge and Y(Fe Cox)255,56. The reason for the kink
2
3
5
4
13
1-x
observed could be that the major contribution of resistivity in MnPt As changes from electron-
5
phonon scattering (at a higher temperature) to electron-electron scattering (below the magnetic
ordering temperature) while it is possible that additional magnetoresistance contribution develops
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
below T . A high-quality single crystal may be necessary for further investigation. The resistivity
c
n
curve was fitted by using a power law (T) =  + AT where  is the residual resistivity due to
0
0
defect scattering, A is a constant and n is an integer determined by the interaction pattern. At high-
temperatures (HT) before the magnetic ordering temperature (310 K-350 K), as shown by the green
line, we found a good fit when n equals 1 which means the resistivity has mainly resulted from the
collision between electrons and phonons. As the temperature goes down, the phonon contribution
decreases significantly, while n is best fitted to be 3 in the low temperature (LT) region(4-25 K).
This confirms that s-d electron scattering is a possible predominant mechanism at low
5
7
temperature. The residual resistivity  for HT and LT regions was fitted to be 18.8 (1) -cm
0
and 3.546 (3) -cm, respectively. The constant A was fitted to be 0.0356 (3) -cm/K in the HT
-5
3
range and a much smaller 3.84 (6) × 10 -cm/K in the LT range.
ACS Paragon Plus Environment

Page 11 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FIG. 4. Temperature-dependence of resistivity for MnPt As under 0 T. Green and blue lines stand
5
for the power law fitting under high & low temperature regions.
Heat Capacity Measurement: The specific heat of MnPt As was measured between 220 K and
5
320 K, as shown in FIG. 5. A clear anomaly can be observed starting from ~300 K with the peak
appearing at ~270 K, which is consistent with the result for the magnetic ordering transition
temperature in magnetic susceptibility measurement. The shape anomaly confirms that the
magnetic phase transition at room temperature is intrinsic in MnPt As. Due to the lack of
5
information for the phonon mode and the noisy high-temperature data, we are not able to calculate
the magnetic entropy change for MnPt As.
5
ACS Paragon Plus Environment

Chemistry of Materials
Page 12 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FIG. 5. Heat capacity measurement conducted between 220 K to 320 K with no applied magnetic
field. The red line is the proposed baseline.
Chemical Bonding and Theoretical Magnetic Structure: To examine the influence of possible
atomic interaction on the structural stability and magnetic properties of MnPt As, DOS and -COHP
5
by TB-LMTO-ASA calculations were performed. Using the local density approximation (LDA),
the DOS curve for MnPt As is illustrated in FIG. 6a, which emphasizes contributions from the Mn
5
and Pt valence orbitals. Most of the DOS curve below -0.5eV belongs to the Pt 5d band; the Fermi
level (–1 ~ +1 eV) is dominated by a combination of Mn and Pt d orbital contributions, which
forms a noticeably sharp and intense peak around 1eV wide. According to the corresponding -
COHP curves, the wavefunctions contributing to this peak have a strong Pt-Mn and Pt-Pt
antibonding character. These features of the LDA-DOS arise from structural influences on the
orbital interactions in MnPt As. In magnetic materials, the tendency of being ferromagnetic
5
ordering can be determined by using the Stoner criterion which requires a value larger than 1 for
the term N(E ) I(Mn). Evaluation of the Stoner criterion using the Mn partial DOS gives
F

1
N(E )I(Mn) = 6.3; where N(E ) = 15.5 eV , and I(Mn) stands for the exchange-correlation integral,
F
F
58
0
.408 eV for Mn. Thus, according to the LDA-DOS curves, MnPt As is susceptible to either a
5
ACS Paragon Plus Environment

Page 13 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
structural distortion or ferromagnetism by breaking the spin degeneracy to eliminate the
antibonding interactions at the Fermi level.
Applying spin polarization via the local spin density approximation (LSDA), the DOS and -COHP
curves for the spin-up and spin-down wavefunctions are illustrated in FIG. 6c-e. It is clearly shown
that the corresponding Fermi levels shift away from the peaks in the DOS curves, and closely
approach the pseudogap in both majority and minority spin DOS curves. Moreover, the Pt-Mn and
Pt-Pt antibonding states vanish. The integration of the spin-up and spin-down contribution yields
a total magnetic moment of 4.55 μ per formula unit for MnPt As. Interestingly, analysis of the
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
B
5
local moments reveals that the magnetic moments arise primarily from the Mn atoms (3.95 B)
and slightly from the Pt atoms (0.12  ). The Stoner product in the spin-polarized situation is 2.6,
B
indicating that ferromagnetic ordering is favored. Further investigation will be needed to determine
the role of the Pt atoms in the Mn-Mn exchange interaction. Moreover, the majority and minority
spin Mn 3d and Pt 5d bands are not fully filled at the Fermi level, which also indicates soft
ferromagnetic behavior. The theoretical calculation confirms what is observed experimentally.
FIG. 6. (a) Partial DOS curves and (b) –COHP curves of MnPt As obtained from non-spin-
5
polarization (LDA). (c) Partial DOS curves and (d, e) –COHP curves of MnPt As obtained from
5
spin-polarization (LSDA).
Electronic Structure Calculation: To estimate the influence of spin-orbit coupling (SOC) on the
magnetic properties in MnPt As, the band structure and density of states (DOS) were also
5
calculated using the WIEN2k program. The electronic structures for MnPt As in FIG. 7a and b
5
ACS Paragon Plus Environment

Chemistry of Materials
Page 14 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
show great consistency with the resistivity measurements, which showed that the compound is
metallic. The LDA band structures with/without SOC reveal that the sharp peak in the DOS
involves the hybridization of Mn 3d and Pt 5d bands that are relatively flat (nearly dispersionless)
near the Brillouin zone boundaries. A saddle point can be observed at the  point near the Fermi
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
level (E ) when SOC is not applied which is broken by SOC when it is included. The SOC effect
F
also opens a gap at some other high-symmetry points. The p orbital of the As atoms and the d
orbitals of Mn and Pt atoms are dominant in the energy range we showed, as can be seen in the
DOS figures. A van Hove singularity from the d orbitals of the Mn atoms can be observed near EF
when SOC is not considered. However, the SOC effect splits the strong peak in DOS near E into
F
two small peaks (indicated by the red arrows). Therefore, the d orbital from the Mn atoms
contribute ~50 % less at E . The Stoner term is calculated to be 8.34 without SOC and 4.41 with
F
considering the SOC effect. The calculated Stoner parameter without SOC from the WIEN2k
program is close to the one obtained for the LMTO calculation. Thus, MnPt As is theoretically
5
ferromagnetic, consistent with the experimental magnetic measurement.
ACS Paragon Plus Environment

Page 15 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FIG. 7. Band structure and density of states (DOS) of MnPt As (a) without and (b) with
5
consideration of spin-orbit coupling (SOC) effect. The red arrows indicate the splitting of van
Hove singularity on DOS near E caused by SOC effect.
F
The three-dimensional Fermi surface demonstrates the distribution of energy bands
crossing the Fermi level in the first Brillouin Zone (BZ). To estimate the SOC effects on the
electronic structure of MnPt As, the Fermi surfaces with/without SOC were generated and are
5
illustrated in FIG. 8. Intuitively, the strong SOC effect on Pt atoms indeed decreases the electronic
st
states within the 1 BZ which also is reflected in the density of states. SOC effect mainly influences
the Fermi surface at/near the high-symmetry points which are marked in FIG. 8 except for the 
point that is at the geometric center of the first BZ. One can easily tell that by introducing the SOC
effect, the saddle point at R disappears. The electronic states near the  point in the center of the
BZ also vanish. Moreover, electronic states near the A and Z points dramatically reduce after the
SOC effect is included.
ACS Paragon Plus Environment

Chemistry of Materials
Page 16 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
FIG. 8. Fermi surface of MnPt As in the first Brillouin Zone of MnPt As (a) without and (b) with
spin-orbit coupling effect considered. Z, R, A, M and X indicate the position of high-symmetry
points.  point is at the geometric center of the first BZ.
5
5
Conclusion
In this paper, we successfully synthesized a new rare-earth-free Pt-rich ferromagnet, MnPt As.
5
The new material displays a layered tetragonal crystal structure with a space group of P4/mmm.
Magnetic property measurements proved that MnPt As is ferromagnetically ordered at room
5
temperature. Resistivity and heat capacity measurements confirm the magnetic property
measurements. The theoretical electronic structure demonstrates that Pt-Mn and Pt-Pt antibonding
interactions are critical to the ferromagnetic properties in MnPt As. Moreover, the spin-orbit
5
coupling effect of Pt atoms is essential in decreasing the density of states of the Mn atoms at EF
by splitting the van Hove singularity at the Fermi level, thus lowering the saturated moment.
Moreover, MnPt As is the first high-T magnetic material with this structure type. It provides a
5
c
great platform to design and investigate new magnetic materials with targeted functional properties.
Supporting Information
The .cif file is listed as supporting information available free of charge via the internet at
https://pubs.acs.org.
Author Information
Corresponding Author: weiweix@lsu.edu.
Notes: The authors declare no competing financial interest.
ACS Paragon Plus Environment

Page 17 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
Acknowledgement
The work at LSU is supported by Beckman Young Investigator award and NSF-DMR-1944965.
Reference
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(1) Morón, C.; Cabrera, C.; Morón, A.; García, A.; González, M. Magnetic Sensors Based on
Amorphous Ferromagnetic Materials: A Review. Sensors 2015, 15, 28340–28366.
(
(
2) Parkin, S.; Yang, S.-H. Memory on the Racetrack. Nat. Nanotech. 2015, 10, 195–198.
3) Averyanov, D. V.; Sadofyev, Y. G.; Tokmachev, A. M.; Primenko, A. E.; Likhachev, I. A.;
Storchak, V. G. Direct Epitaxial Integration of the Ferromagnetic Semiconductor EuO with
Silicon for Spintronic Applications. ACS Appl. Mater. Interfaces 2015, 7, 6146–6152.
(4) Mahmoud, W. E.; Al-Ghamdi, A. A.; Al-Agel, F. A.; Al-Arfaj, E.; Shokr, F. S.; Al-Gahtany,
S. A.; Alshahrie, A.; Shirbeeny, W.; Bronstein, L. M.; Beall, G. W. Highly Ferromagnetic,
Transparent Conducting Electrode Based on Ce Cu O Thin Film for Spintronic
1
−x
x
2
Applications. Ceram. Int. 2015, 41, 9101–9106.
(5) Chumak, A. V.; Vasyuchka, V. I.; Serga, A. A.; Hillebrands, B. Magnon Spintronics. Nat.
Phys. 2015, 11, 453–461.
(
6) Sengupta, A.; Shim, Y.; Roy, K. Proposal for an All-Spin Artificial Neural Network:
Emulating Neural and Synaptic Functionalities Through Domain Wall Motion in
Ferromagnets. IEEE Trans. Biomed. Circuits Syst. 2016, 10, 1152–1160.
7) Patel, K.; Zhang, J.; Ren, S. Rare-Earth-Free High Energy Product Manganese-Based
Magnetic Materials. Nanoscale 2018, 10, 11701–11718.
(
(
8) Li, D.; Li, Y.; Pan, D.; Zhang, Z.; Choi, C.-J. Prospect and Status of Iron-Based Rare-Earth-
Free Permanent Magnetic Materials. J. Magn. Magn. Mater. 2019, 469, 535–544.
(9) Yüzüak, G. D.; Yüzüak, E.; Elerman, Y. Hf Co Thin Films: Rare-Earth-Free Permanent
2
11
Nanomagnets. Thin Solid Films 2017, 625, 115–121.
(
10) López-Ortega, A.; Lottini, E.; Fernández, C. de J.; Sangregorio, C. Exploring the Magnetic
Properties of Cobalt-Ferrite Nanoparticles for the Development of a Rare-Earth-Free
Permanent Magnet. Chem. Mater. 2015, 27, 4048–4056.
th
(11) Kittel, Charles Introduction to Solid State Physics. 8 Edition, Wiley, US, 1996.
(
12) Mohapatra, J.; Liu, J. P. Chapter 1-Rare-Earth-Free Permanent Magnets: The Past and
Future. In Handbook of Magnetic Materials; Brück, E., Ed.; Elsevier, Oxford, United
Kingdom, 2018; Vol. 27, pp 1–57.
(
13) Cui, J.; Kramer, M.; Zhou, L.; Liu, F.; Gabay, A.; Hadjipanayis, G.; Balasubramanian, B.;
Sellmyer, D. Current Progress and Future Challenges in Rare-Earth-Free Permanent
Magnets. Acta Mater. 2018, 158, 118–137.
(14) Ibrahim, M.; Masisi, L.; Pillay, P. Design of Variable-Flux Permanent-Magnet Machines
Using Alnico Magnets. IEEE Trans. Ind. Appl. 2015, 51, 4482–4491.
(15) Campbell, R. B.; Julien, C. A. Structure of Alnico V. J. Appl. Phys. 1961, 32, S192–S194.
(
16) Julien, C. A.; Jones, F. G. Alpha‐Sub‐Gamma Phase in Alnico 8 Alloys. J. Appl. Phys. 1965,
6, 1173–1174.
3
(17) Zhou, L.; Miller, M. K.; Lu, P.; Ke, L.; Skomski, R.; Dillon, H.; Xing, Q.; Palasyuk, A.;
McCartney, M. R.; Smith, D. J.; et al. Architecture and Magnetism of Alnico. Acta Mater.
2
014, 74, 224–233.
ACS Paragon Plus Environment

Chemistry of Materials
Page 18 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
(
18) Zhou, L.; Tang, W.; Ke, L.; Guo, W.; Poplawsky, J. D.; Anderson, I. E.; Kramer, M. J.
Microstructural and Magnetic Property Evolution with Different Heat-Treatment
Conditions in an Alnico Alloy. Acta Mater. 2017, 133, 73–80.
(19) Patel, K.; Zhang, J.; Ren, S. Rare-Earth-Free High Energy Product Manganese-Based
Magnetic Materials. Nanoscale 2018, 10, 11701–11718.
(20) Kōno, H. On the Ferromagnetic Phase in Manganese-Aluminum System. J. Phys. Soc. Jpn.
958, 13, 1444–1451.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
(21) Koch, A. J. J.; Hokkeling, P.; v. d. Steeg, M. G.; de Vos, K. J. New Material for Permanent
Magnets on a Base of Mn and Al. J. Appl. Phys. 1960, 31, S75–S77.
(22) Shukla, A.; Pelton, A. D. Thermodynamic Assessment of the Al-Mn and Mg-Al-Mn
Systems. J. Phase Equilib. Diffus. 2009, 30, 28–39.
(23) Park, J. H.; Hong, Y. K.; Bae, S.; Lee, J. J.; Jalli, J.; Abo, G. S.; Neveu, N.; Kim, S. G.;
Choi, C. J.; Lee, J. G. Saturation Magnetization and Crystalline Anisotropy Calculations for
MnAl Permanent Magnet. J. Appl. Phys. 2010, 107, 09A731.
(24) Manchanda, P.; Kashyap, A.; Shield, J. E.; Lewis, L. H.; Skomski, R. Magnetic Properties
of Fe-Doped MnAl. J. Magn. Magn. Mater. 2014, 365, 88–92.
(25) Anand, K.; Pulikkotil, J. J.; Auluck, S. Study of Ferromagnetic Instability in τ-MnAl, Using
First-Principles. J. Alloys Compd. 2014, 601, 234–237.
(26) Braun, P. B.; Goedkoop, J. A. An X-Ray and Neutron Diffraction Investigation of the
Magnetic Phase Al0.89Mn1.11. Acta Cryst. 1963, 16, 737–740.
(27) Tu Chen; Stutius, W. The Phase Transformation and Physical Properties of the MnBi and
Mn1.08Bi Compounds. IEEE Trans. Magn. 1974, 10, 581–586.
(
28) Cui, J.; Choi, J. P.; Li, G.; Polikarpov, E.; Darsell, J.; Kramer, M. J.; Zarkevich, N. A.; Wang,
L. L.; Johnson, D. D.; Marinescu, M.; et al. Development of MnBi Permanent Magnet:
Neutron Diffraction of MnBi Powder. J. Appl. Phys. 2014, 115, 17A743.
(29) Yang, Y. B.; Chen, X. G.; Guo, S.; Yan, A. R.; Huang, Q. Z.; Wu, M. M.; Chen, D. F.;
Yang, Y. C.; Yang, J. B. Temperature Dependences of Structure and Coercivity for Melt-
Spun MnBi Compound. J. Magn. Magn. Mater. 2013, 330, 106–110.
(
30) McGuire, M. A.; Cao, H.; Chakoumakos, B. C.; Sales, B. C. Symmetry-Lowering Lattice
Distortion at the Spin Reorientation in MnBi Single Crystals. Phys. Rev. B 2014, 90, 174425.
31) Zarkevich, N.A.; Wang, L.L.; Johnson, D.D. Anomalous Magneto-Structural Behavior of
MnBi Explained: A Path Towards an Improved Permanent Magnet. APL Mater. 2014, 2,
(
0
32103.
(
(
(
(
32) Cui, J.; Choi, J.-P.; Polikarpov, E.; Bowden, M. E.; Xie, W.; Li, G.; Nie, Z.; Zarkevich, N.;
Kramer, M. J.; Johnson, D. Effect of Composition and Heat Treatment on MnBi Magnetic
Materials. Acta Mater. 2014, 79, 374–381.
33) Brabers, J.H.V.J.; Buschow, K.H.J.; De Boer, F.R. Field-Induced First-Order
Antiferromagnetic-Ferromagnetic Transitions in RMn Ge Compounds and Their Relation
2
2
to the Magnetostriction of the Mn Sublattice. Phys. Rev. B 1999, 59, 9314.
34) Brabers, J.H.V.J.; Duijn, V.H.M.; De Boer, F.R.; Buschow, K.H.J. Magnetic Properties of
Rare-Earth Manganese Compounds of the RMn Ge Type. J. Alloy Compd. 1993, 198, 127-
32.
35) Brabers, J.H.V.J.; Nolten, A.J.; Kayzel, F.; Lenczowski, S.H.J.; Buschow, K.H.J.; De Boer,
F.R. Strong Mn-Mn Distance Dependence of the Mn Interlayer Coupling in SmMn Ge -
6
6
1
2
2
Related Compounds and Its Role in Magnetic Phase Transitions. Phys. Rev. B 1994, 50,
16410.
ACS Paragon Plus Environment

Page 19 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
(
36) Beleanu, A.; Kiss, J.; Kreiner, G.; Köhler, C.; Müchler, L.; Schnelle, W.; Burkhardt, U.;
Chadov, S.; Medvediev, S.; Ebke, D.; et al. Large Resistivity Change and Phase Transition
in the Antiferromagnetic Semiconductors LiMnAs and LaOMnAs. Phys. Rev. B 2013, 88,
1
84429.
(37) Petrovic, C.; Pagliuso, P.G.; Hundley, M.F.; Movshovich, R.; Sarrao, J.L.; Thompson, J.D.;
Fisk, Z.; Monthoux, P. Heavy-Fermion Superconductivity in CeCoIn at 2.3 K. J. Phys.
5
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Condens. Matter 2001, 13, p.L337.
(
38) Schulz, S.; Nechaev, I.A.; Güttler, M.; Poelchen, G.; Generalov, A.; Danzenbächer, S.;
Chikina, A.; Seiro, S.; Kliemt, K.; Vyazovskaya, A.Y.; Kim, T.K. Emerging 2D-
Ferromagnetism and Strong Spin-Orbit Coupling at the Surface of Valence-Fluctuating
EuIr Si . npj Quantum Mater. 2019, 4, 26.
2
2
(39) Khan, S. A.; Blaha, P.; Ebert, H.; Minár, J.; Šipr, O. Magnetocrystalline Anisotropy of FePt:
A Detailed View. Phys. Rev. B 2016, 94, 144436.
(40) Kabir, A.; Hu, J.; Turkowski, V.; Wu, R.; Camley, R.; Rahman, T. S. Effect of Structure on
the Magnetic Anisotropy of L1 FePt Nanoparticles. Phys. Rev. B 2015, 92, 054424.
0
(41) Pfisterer, M.; Nagorsen, G. Zur Struktur Ternärer Übergangsmetallarsenide/On the
Structure of Ternary Arsenides. Z. Naturforsch. B 2014, 35, 703–704.
(42) Jesus, S.; Borges, O. Recent Developments in the Nasal Immunization against Anthrax.
WJV 2011, 01, 79–91.
(
(
43) Sheldrick, G. M. Crystal Structure Refinement with SHELXL. Acta Cryst C 2015, 71, 3–8.
44) Bruker. Smart; Bruker AXS Inc.: Madison, WI, USA, 2012 URL:
https://www.bruker.com/products/x-ray-diffraction-and-elemental-analysis/single-crystal-
x-ray-diffraction/sc-xrd-software/overview/sc-xrd-software/apex3.html. Date of access:
th
April 10 , 2020.
(45) Walker, N.; Stuart, D. An Empirical Method for Correcting Diffractometer Data for
Absorption Effects. Acta Cryst. A 1983, 39, 158–166.
(
46) Elstner, M.; Porezag, D.; Jungnickel, G.; Elsner, J.; Haugk, M.; Frauenheim, Th.; Suhai, S.;
Seifert, G. Self-Consistent-Charge Density-Functional Tight-Binding Method for
Simulations of Complex Materials Properties. Phys. Rev. B 1998, 58, 7260–7268.
(47) Andersen, O. K.; Jepsen, O. Explicit, First-Principles Tight-Binding Theory. Phys. Rev. Lett.
1
984, 53, 2571–2574.
(48) Krier, G., Jepsen, O.; Burkhardt, A.; Andersen, O.K. The TB-LMTO-ASA
program. Stuttgart, 1995, April.
(49) Blaha, P.; Schwarz, K.; Sorantin, P.; Trickey, S. B. Full-Potential, Linearized Augmented
Plane Wave Programs for Crystalline Systems. Comput. Phys. Commun. 1990, 59, 399–
4
15.
(50) Wimmer, E.; Krakauer, H.; Weinert, M.; Freeman, A. J. Full-Potential Self-Consistent
Linearized-Augmented-Plane-Wave Method for Calculating the Electronic Structure of
Molecules and Surfaces: O Molecule. Phys. Rev. B 1981, 24, 864–875.
2
(
(
(
51) Perdew, J. P.; Wang, Y. Accurate and Simple Analytic Representation of the Electron-Gas
Correlation Energy. Phys. Rev. B 1992, 45, 13244–13249.
52) King-Smith, R. D.; Vanderbilt, D. Theory of Polarization of Crystalline Solids. Phys. Rev.
B 1993, 47, 1651–1654.
53) Zieba, A.; Selte, K.; Kjekshus, A.; Andresen, A. F. Phase Transitions in MnAs. Acta Chem.
Scand. A 1978, 32, 173-177.
ACS Paragon Plus Environment

Chemistry of Materials
Page 20 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
(
54) Yang, J.B.; Yang, Y.B.; Chen, X.G.; Ma, X.B.; Han, J.Z.; Yang, Y.C.; Guo, S.; Yan, A.R.;
Huang, Q.Z.; Wu, M.M.; Chen, D.F. Anisotropic Nanocrystalline MnBi with High
Coercivity at High Temperature. Appl. Phys. Lett. 2011, 99, 082505.
(
55) Soudé, A.; Pikul, A. P.; Wiśniewski, P.; Tougait, O.; Pasturel, M.; Kaczorowski, D.; Noël,
H. Magnetic, Electric and Thermoelectric Properties of Ternary Intermetallics from the Ce–
Co–Ge System. Intermetallics 2011, 19, 1201-1206.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(
(
(
56) Guzdek, P.; Pszczoła, J.; Chmist, J.; Stoch, P.; Stoch, A.; Suwalski, J. Electrical Resistivity
and Mössbauer Effect Studies of Y(Fe1− xCo ) Intermetallics. J. Alloy. Compd., 520, 72-76.
x 2
57) Meaden, G. T. Electrical Resistance of Metals; The International Cryogenics Monograph
Series; Springer US, 1965.
58) Janak, J. F. Uniform Susceptibilities of Metallic Elements. Phys. Rev. B 1977, 16, 255–262.
ACS Paragon Plus Environment

Page 21 of 22
Chemistry of Materials
1
2
3
4
5
6
7
8
9
Table 1. Single crystal structure refinement for MnPt As at 296 (2) K.
5
Refined Formula
F.W. (g/mol)
Space group; Z
a(Å)
MnPt As
5
1105.31
P 4/mmm; 1
3.931 (1)
7.092 (1)
109.58 (5)
2.872-36.301
1489; 0.0408
200
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
c(Å)
V (Å3)
θ range (º)
No. reflections; Rint
No. independent reflections
No. parameters
R : ωR (I>2(I))
11
0.0275; 0.0730
1.165
1
2
Goodness of fit
Diffraction peak and hole (e / Å )
-
3
4.430; -5.266
Table 2. Atomic coordinates and equivalent isotropic displacement parameters for MnPt As at
5
2
2
96 (2) K. (U is defined as one-third of the trace of the orthogonalized U tensor (Å ))
eq
ij
Atom Wyckoff.
Occ.
x
y
z
Ueq
Pt1
Pt2
4i
1a
1b
1c
1
1
1
1
0
½
0.2794 (1) 0.0063 (2)
0
0
0
0
0
½
0
0.0058 (2)
0.0066 (5)
0.0073 (8)
As3
Mn4
½
½
Table 3. Anisotropic thermal displacements from MnPt As.
5
Atom
Pt1
U11
U22
U33
U23
U13
U12
0.0064 (2)
0.0060 (3)
0.0069 (7)
0.008 (1)
0.0050 (2)
0.0060 (3)
0.0069 (7)
0.008 (1)
0.0075 (3)
0.0052 (4)
0.006 (1)
0.006 (2)
0
0
0
0
0
0
0
0
0
0
0
0
Pt2
As3
Mn4
ACS Paragon Plus Environment

Chemistry of Materials
Page 22 of 22
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
For table of content only
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
ACS Paragon Plus Environment