12044-16-5Relevant articles and documents
Superconductivity in CeO1-xFxFeAs with upper critical field of 94 T
Prakash,Singh,Patnaik,Ganguli
, p. 82 - 85 (2009)
We have successfully synthesized Ce based oxypnictide superconductors with fluorine doping (CeO1-xFxFeAs) by a two step solid state reaction method. Detailed XRD and EDX confirm the crystal structure and chemical compositions. We obs
Enhancement in transition temperature and upper critical field of CeO 0.8F0.2FeAs by yttrium doping
Prakash,Singh,Banerjee,Patnaik,Ganguli
, (2009)
We report significant enhancement in superconducting properties of yttrium substituted Ce1-xYxOFFeAs superconductors. The polycrystalline samples were prepared by two step solid state reaction technique. X-ray diffraction confirmed t
Next-nearest neighbour contributions to the XPS binding energies and XANES absorption energies of P and As in transition-metal arsenide phosphides MAs 1-yPy having the MnP-type structure
Grosvenor, Andrew P.,Cavell, Ronald G.,Mar, Arthur
, p. 2549 - 2558 (2008)
X-ray photoeleetron spectroscopic (XPS) and X-ray absorption near-edge spectroscopic (XANES) measurements have been made for several series of metal arsenide phosphides MAs1-yPy, (M= Co, Fe, Cr) that adopt the MnP-type structure. The P and As XPS binding energies (BEs) and XANES absorption energies of the metal arsenide phosphides do not follow the trend observed for the simple binary phosphides or arsenides, a deviation that arises from the combination of nearest and nextnearest neighbour contributions acting on the P or As photoemission or absorption site. The P 2p3/2 BEs and K-edge absorption energies are lower in MAs1-yPy than in MP because the P atoms are more negatively charged and because the P photoemission or absorption site is screened to a greater extent by less positively charged nearest-neighbour M atoms and more negatively charged next-nearest neighbour P atoms. The As L3- and K-edge absorption energies are higher in MAs1-yPy than in MAs primarily because the As atoms are less negatively charged. The M charge has been evaluated from analysis of the M 2p XPS spectra and the M L- and K-edge XANES spectra.
Superconductivity of the platinum doped 122 iron arsenide SrFe 2-xPtxAs2
Zhang,Guo,Li,Wang,Yamaura,Takayama-Muromachi
, p. 600 - 602 (2011)
Pt doped 122 iron arsenide SrFe1-xPt xAs2 (0 ≤ x ≤ 0.4) was successfully synthesized. The tetragonal unit-cell volume and the lattice constant a increase with increasing the Pt content, while c decreases, suggesting that the Fe ions are indeed replaced by Pt ions. By the Pt doping, the magnetic order of the parent phase is suppressed, and superconductivity emerges at approximately x = 0.15. T c reaches the maximum of 16 K at x = 0.2. The compounds series can be a suitable subject to investigate role of the doped 5d state in the superconducting 3d Fe-As layer.
The synthesis and characterization of LiFeAs and NaFeAs
Chu,Chen,Gooch,Guloy,Lorenz,Lv,Sasmal,Tang,Tapp,Xue
, p. 326 - 331 (2009)
The newest homologous series of superconducting Fe-pnictides, LiFeAs (Li111) and NaFeAs (Na111) have been synthesized and investigated. Both crystallize with the layered tetragonal anti-PbFCl-type structure in P4/nmm space group. Polycrystalline samples a
Structures of the ternary iron germanium pnictides FeGe1-xPnx (Pn = P, As, Sb)
Mills, Allison M.,Mar, Arthur
, p. 82 - 92 (2000)
The pseudo-binary FeGe-FePn (Pn = P, As, Sb) systems have been investigated by X-ray diffraction methods. The phosphide and arsenide systems form ternary solid solutions FeGe1-xPx (0.4≤x≤1.0) and FeGe1-xAsx (0.3≤x≤1.0) crystallizing in MnP-type structures. The antimonide system is more complex, forming intermetallic compounds that display incipient ordering of Sb2 pairs as they are stuffed into the FeGe (x = 0) structure while Ge atoms are gradually removed. The structures of an intermediate member FeGe0.80Sb0.20 (x = 0.20) and of the limiting member FeGe0.67Sb0.33 (x = 0.33) in this progression were determined by single-crystal X-ray diffraction. Both compounds crystallize in hexagonal space groups: P63/mmc, a = 8.796(2), c = 8.004(2) angstroms, Z = 6 for Fe3Ge2.4Sb0.6 (or FeGe0.80Sb0.20), and P6/mmm, a = 8.9885(5), c = 7.9043(6) angstroms, Z = 6 for Fe3Ge2Sb (or FeGe0.67Sb0.33). Beyond this point, ternary solid solutions FeGe1-xSbx (0.4≤x≤1.0) are formed, crystallizing in NiAs-type structures.
A safe low temperature route to nanocrystalline transition metal arsenides
Xie, Yi,Lu, Jun,Yan, Ping,Jiang, Xuchuan,Qian, Yitai
, p. 114 - 115 (2000)
Nanocrystalline FeAs, CoAs and NiAs were prepared by keeping the mixture of FeCl3, CoCl2 or NiCl2 with arsenic and KBH4 in ethylenediamine (en) at 100 °C for 4 h, respectively. X-Ray powder diffraction (XRD) patterns and transmission electron microscope (TEM) images show that the products are orthorhombic FeAs, CoAs and hexagonal NiAs, respectively, and all are well crystalline in nanometers.
A Self-Doped Oxygen-Free High-Critical-Temperature (High- Tc) Superconductor: SmFFeAs
Lin, Dan,Xu, Han-Shu,Luo, Jingjing,Huang, Haoliang,Lu, Yalin,Tang, Kaibin
, (2019)
A new iron-base superconductor SmFFeAs is synthesized via solid-state metathesis reaction by using SmFCl and LiFeAs as precursors. The compound crystallized in the tetragonal ZrCuSiAs-type structure with the space group P4/nmm and lattice parameters of a = 3.9399(0) ? and c = 8.5034(1) ?. The superconducting diamagnetic transition occurs at 56 K for the parent compound, which confirmed by the resistivity and magnetic susceptibility. The appearance of superconductivity without extrinsic doping could be ascribed to the self-doping owing to the mixed valence of Sm ions. The as-synthesized SmFFeAs serves as a new self-doped parent compound for oxygen-free high-critical-temperature (high-Tc) superconductors.
Doping dependence of magnetic and transport properties in single crystalline Co-doped BaFe2As2
Nakajima, Yasuyuki,Taen, Toshihiro,Tamegai, Tsuyoshi
, p. S408-S410 (2010)
We report the doping dependence of transport and magnetic properties in Co-doped BaFe2As2. With increasing Co concentration x, structural and magnetic transitions are suppressed and superconductivity emerges in the range of 0.3c at low temperatures and low fields obtained from bulk magnetization is reasonably large and the doping dependence shows a maximum at x～0.07 similar to Tc. The values of Jc at low temperatures reach about 1×106A/cm2 around the optimally doped region, which is potentially attractive for technological applications.
Superconductivity of "1 1 1"-type iron arsenide compounds
Wang,Liu,Yang,Lv,Gao,Zhang,Yu,Jin
, p. S307-S308 (2010)
"1 1 1"-type iron arsenide compounds AFeAs (A = Li, Na) were synthesized. These compounds crystallize into Cu2Sb type tetragonal layered structure with space group P4/nmm and show superconductivity with the transition temperature ～18 K for LiFe
