Search for perovskite-type new borides in the Sc-TM-B (TM = Ti, V, Cr, Mn, Fe, Co, and Ni) systems

Article abstract of DOI:10.1016/j.jallcom.2004.04.060

A search for perovskite-type new borides in the Sc-TM-B (TM = Ti, V, Cr, Mn, Fe, Co, and Ni) system has been carried out by the arc-melting synthetic method. As a result, the chemical formula of the compound ScNi₃B _0.5 was obtained. This compound has the cubic perovskite-type structure (space group: Pm3m) with the lattice parameter a = 0.37760(7)nm. ScNi₃B_0.5 exhibits metallic behavior down to 4.2K. The magnetic susceptibility of ScNi₃B_0.5 shows Pauli paramagnetism. No superconductivity appears down to the lowest temperature by the electric and magnetic measurements. The micro-Vickers hardness and oxidation resistivity in air are also reported for ScNi₃B _0.5.

Full text of DOI:10.1016/j.jallcom.2004.04.060

Journal of Alloys and Compounds 383 (2004) 294–297
Search for perovskite-type new borides in the Sc-TM-B (TM = Ti, V, Cr,
Mn, Fe, Co, and Ni) systems
T. Shishidoa,∗, K. Kudoub, T. Sasakia, S. Okadac, J. Yed, K. Iizumie, A. Nomuraa,
T. Sugawaraa, K. Obaraa, M. Tanakaf, S. Kohikig, Y. Kawazoea, K. Nakajimaa, M. Okua
a
Institute for Materials Research, Tohoku University, 2-1-1 Katahira-cho, Aoba-ku, Sendai 980-8577, Japan
b
Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
c
Faculty of Engineering, Kokushikan University, 4-28-1 Setagaya-ku, Tokyo 154-8515, Japan
d
National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan
e
Faculty of Engineering, Tokyo Institute of Polytechnics, 1583 Iiyama, Atsugi 243-0297, Japan
f
Photon Factory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
g
Department of Materials Science, Kyusyu Institute of Technology, Kita-Kyusyu 804-8550, Japan
Abstract
A search for perovskite-type new borides in the Sc-TM-B (TM = Ti, V, Cr, Mn, Fe, Co, and Ni) system has been carried out by the
arc-melting synthetic method. As a result, the chemical formula of the compound ScNi3B0.5 was obtained. This compound has the cu-
bic perovskite-type structure (space group: Pm3m) with the lattice parameter a = 0.37760(7) nm. ScNi3B0.5 exhibits metallic behavior
down to 4.2 K. The magnetic susceptibility of ScNi3B0.5 shows Pauli paramagnetism. No superconductivity appears down to the lowest
temperature by the electric and magnetic measurements. The micro-Vickers hardness and oxidation resistivity in air are also reported for
ScNi3B0.5
.
© 2004 Elsevier B.V. All rights reserved.
Keywords: Perovskite-type boride; Electric property; Magnetic property; Hardness; Oxidation resistivity
1. Introduction
2. Experimental details
Many studies of simple and complex perovskite-type
oxides have been performed due to the interesting features
as the superconductivity, the metal–insulator transition, ion
conduction characteristics, dielectric properties, and ferro-
elasticity [1–4]. On the other hand, there have been few
studies on the non-oxide perovskite-type compound [5–8].
Systematic investigation of the synthesis and fundamental
characterization of the non-oxide perovskite-type com-
pounds is necessary.
2.1. Synthesis
Polycrystalline samples of Sc-TM-B system were pre-
pared by the arc melting method using 99.9% Sc (tips),
99.9% TM elements (tips) and 99.8% B (powder) as raw
materials. These were weighed in the atomic ratio Sc:TM:B
= 1:3:1. The mixture of the starting materials, about 2 g for
each sample, was placed on the water-cooled copper hearth
in the reaction chamber. Argon was used as a protective at-
mosphere. A small amount of the residual oxygen in argon
was eliminated by fusing a button of titanium. The starting
materials were then melted for 3 min by argon arc plasma
flame with dc power source at 20 and 100 Å. The samples
were then turned over and melted three times under the same
condition. Finally, synthesized samples were wrapped in the
tantalum foil and annealed at 1573 K for 20 h under vacuum
to ensure homogeneity.
In this study, we focus on the search for perovskite-type
new ternary borides in the Sc-TM-B systems (TM = Ti, V,
Cr, Mn, Fe, Co, and Ni).
∗
Corresponding author. Tel.: +81-22-215-2233;
fax: +81-22-215-2202.
E-mail address: shishido@imr.tohoku.ac.jp (T. Shishido).
0925-8388/$ – see front matter © 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jallcom.2004.04.060

T. Shishido et al. / Journal of Alloys and Compounds 383 (2004) 294–297
295
2.2. Characterization
For the chemical analysis, the samples were fused using
NaHSO4 as a flux reagent. The obtained material was then
dissolved in HCl. The chemical composition of each solu-
tion was analyzed by induction coupled plasma atomic emis-
sion spectrometry (ICP-AES), using Zn as the internal stan-
dard. Crystal structure characterization of the samples was
performed by X-ray powder diffraction (XRD). The electri-
cal resistivity of the samples was measured by means of a
dc four probe method from 0.5 K to room temperature. The
magnetic susceptibility measurements were performed in a
field of 5000 Oe using a commercial SQUID magnetometer
(Quantum Design Inc., MPMS-5) from 5 K to room temper-
ature. The micro-Vickers hardness of the crystals was mea-
sured at room temperature. A load of 300 g was applied for
15 s and 10 impressions were recorded for the crystals. TG
and DTA were performed between room temperature and
1473 K to study the oxidation resistivity of the crystals in
air. A pulverized sample of about 25 mg was heated at a rate
Fig. 2. Powder XRD patterns for ScNi3Bx; (a) x = 1.00 (20 at.% B), (b)
x = 0.71 (15 at.% B), (c) x = 0.50, (d) x = 0.44 (10 at.% B), and (e) x
= 0.21 (5 at.% B).
of 10 K min−1
.
Fig. 1 shows powder XRD patterns for the Sc-TM-B (TM
= Ti, V, Cr, Mn, Fe, Co, and Ni) systems. As result, a
new perovskite-type boride has been obtained in the sys-
tem of Sc-Ni-B. Fig. 2 shows the powder XRD patterns for
ScNi3Bx; (a) x = 1.00 (20 at.% B), (b) x = 0.71 (15 at.%
B), (c) x = 0.50, (d) x = 0.44 (10 at.% B), and (e) x = 0.21
(5 at.% B). In the case of (c), boron content x = 0.5, the XRD
pattern corresponds to an almost single phase sample. Other
samples include different phase(s). So we conclude that the
chemical formula of the compound is ScNi3B0.5. This com-
pound has the cubic perovskite-type structure (space group:
Pm3m) with the lattice parameter a = 0.37760(7) nm. In the
structure, Sc is at the corners of the cube. Ni is at the six
face-centered sites and B at the body-centered site.
3. Results and discussion
The arc melted samples were silver in color and exhib-
ited a metallic lustre. The result of the chemical analysis
shows that the chemical compositions before and after syn-
thesis are almost the same. In addition, contamination from
the electrode (tungsten) and hearth (copper) could be disre-
garded in this study.
Fig. 1. Powder XRD patterns for the Sc-TM-B (TM = Ti, V, Cr, Mn, Fe,
Co, and Ni) system; nominal composition is Sc:TM:B = 1:3:1 (atomic
ratio).
Fig. 3. Temperature dependence of the electrical resistivity for ScNi3B0.5
.

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T. Shishido et al. / Journal of Alloys and Compounds 383 (2004) 294–297
One of the important mechanical properties, the hardness
[9,10], is measured for ScNi3B0.5. The micro-Vickers hard-
ness for the ScNi3B0.5 is 4.6 0.1 GPa.
Fig. 5 shows TG-DTA curves for ScNi3B0.5. The TG
analysis indicates that the onset temperature of the oxida-
tion for ScNi3B0.5 is 923 K. Sharp exothermic peaks of the
DTA curve appeared at 1014 and 1082 K. The weight gain of
ScNi3B0.5 by heating in air up to 1473 K is 19.47%. Sc2O3,
ScNiO3, and Ni are identified as the oxidation products of
ScNi3B0.5
.
4. Conclusions
A search for perovskite-type new borides in the Sc-TM-B
(TM = Ti, V, Cr, Mn, Fe, Co, and Ni) system has been
carried out. We can draw the following conclusions from
this study:
Fig. 4. Temperature dependence of the magnetization in H = 5000 Oe for
ScNi3B0.5
.
(1) A new perovskite-type boride has been discovered only
Fig. 3 shows the temperature dependence of the electrical
resistivity for ScNi3B0.5. The ScNi3B0.5 exhibits metallic
behavior down to 4.2 K. No super-conductivity appears at
the lowest temperature.
Fig. 4 shows the temperature dependence of the mag-
netization of ScNi3B0.5 in a field H = 5000 Oe. Magnetic
susceptibilities for ScNi3B0.5 show Pauli paramagnetic
behavior. No trace of superconductivity is found down
to 2 K.
for TM = Ni, the chemical formula of the compound is
ScNi3B0.5
.
(2) ScNi3B0.5 has cubic perovskite-type of structure
(space group: Pm3m) with the lattice parameter a
= 0.37760(7) nm.
(3) ScNi3B0.5 exhibits metallic behavior.
(4) The magnetic susceptibility of ScNi3B0.5 shows Pauli
paramagnetism.
(5) The micro-Vickers hardness of ScNi3B0.5 is 4.6
0.1 GPa.
(6) TG analysis indicates that the onset temperature of oxi-
dation for ScNi3B0.5 is 923 K. Exothermic peaks in the
DTA curve are found at 1014 and 1082 K.
Acknowledgements
This study was performed under the Interuniversity Co-
operative Research Program of the Laboratory for Advanced
Materials (LAM), Institute for Materials Research (IMR),
Tohoku University. We are grateful to Dr. K. Takada and
Mr. M. Ishikuro of IMR for their help with the chemical
analyses.
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