Structure and superconductivity studies on ternary equiatomic silicides,MM′Si
TL;DR: In this article, a series of ternary equiatiomic transition metal silicides have been synthesized and characterized, and the observed properties are explained in terms of the electronic charge transfer effects and crystal structures adopted by these metal excess ternaries.
Abstract: A series of ternary equiatiomic transition metal silicidesMM′Si (M=Zr, Nb, Ta;M′=Ru, Re) and Zr1/2
M
1/2 RuSi (M=Nb, Ta) have been synthesized and characterized. Guinier x-ray data clearly indicate that the compoundsMM′Si (M=Nb, Ta;M′=Ru, Re) crystallize with the orthorhombic TiFeSi-structure. This is contrary to one of the literature reports ascribing the hexagonal ZrRuSi structure toMReSi,M=Nb, Ta. ZrRuSi and Zr1/2
M
1/2RuSi (M=Nb, Ta), however, crystallize with the ZrRuSi structure. All the compounds are metallic and exhibit small and negative Seebeck coefficients. Superconductivity has been discovered inMM′Si,M=Nb, Ta;M′=Ru, Re and the transition temperatures, as measured by the low frequency a.c. susceptibility technique, range from 2·7 to 5·1 K. Zr1/2Nb1/2RuSi is not superconducting above 2·2 K. The observed properties are explained in terms of the electronic charge transfer effects and crystal structures adopted by these metal excess ternary silicides.
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TL;DR: In this paper, the complete series of the MTSi compounds (with M = Ti,Zr,Hf and T = Fe,Ru,Os,Co,Rh,Ir) has been obtained.
14 citations
TL;DR: In this article, it was shown that the TiNiSi-type structure favors superconductivity in ternary germanides as previously found for ternaries silicides.
12 citations
TL;DR: In this paper, the ternary noncentrosymmetric superconductors TaXSi (X=Re, Ru) were investigated by magnetization, resistivity, and specific heat measurements.
Abstract: We have investigated the ternary noncentrosymmetric superconductors TaXSi (X=Re, Ru) by magnetization, resistivity, and specific heat measurements. The samples crystallize in orthorhombic TiFeSi structure having superconducting transition Tc = 5.32 K and 3.91 K, for TaReSi and TaRuSi respectively. Specific heat measurements indicated an s-wave nature of both materials with a moderately coupled nature. However, a low value of specific heat jump and the concave nature of the upper critical field suggests a nontrivial superconducting gap.
10 citations
TL;DR: In this article, a superconducting transition Tc = 5.32 K and 3.91 K for TaReSi and TaRuSi, respectively, and a low value of specific heat jump and the upper critical field concave nature suggests a nontrivial superconducted gap.
Abstract: Ternary noncentrosymmetric superconductors TaXSi (X = Re, Ru) investigated by magnetization, resistivity, and specific heat measurements. It crystallize in the orthorhombic TiFeSi-type structure with superconducting transition Tc = 5.32 K and 3.91 K for TaReSi and TaRuSi, respectively. A low value of specific heat jump and the upper critical field concave nature suggests a nontrivial superconducting gap.
9 citations
TL;DR: In this article, the structural, mechanical and electronic properties of ternary equiatomic NbXSi (X = Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt) compounds are investigated.
9 citations
References
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TL;DR: In this article, the occurrence and structural features of these five structure types together with the tetragonal PbFCl type, an Fe2As-type derivative found earlier for RFeSi and RCoSi compounds were discussed.
Abstract: Over 100 new equiatomic ternary rare earth (R)-transition metal (T) silicides, germanides and gallides were synthesized and structurally analysed either by evaluating powder diffraction photographs or in the case of ScRhSi, ScPtSi, YNiSi, ScRuGe and PrPtGe by refining single-crystal diffraction data. The hexagonal ZrNiAl type, an Fe2P-type derivative, was found for ScRuSi and ScTGe (T ≡ Ru, Rh, Pd, Os). The orthorhombic TiNiSi type, a PbCl2-type derivative, was assigned to RRhGa (R ≡ Er, Y), RPdGa (R ≡ La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, Y, Sc), RIrGa (R ≡ Er, Y), RPtGa (R ≡ La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc), YNiSi, RRhSi (R ≡ Er, Y, Sc), ScPdSi, RIrSi (R ≡ Gd, Er, Y, Sc), RPtSi (R ≡ Tb, Dy, Ho, Er, Tm, Lu, Y, Sc), RRhGe (R ≡ Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y, Sc), RIrGe (R ≡ Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y, Sc) and RPtGe (R ≡ Sm, Gd, Tb, Dy, Ho, Er, Tm, Y, Sc). The CeCu2 type, which is related to TiNiSi, was found for R(Pd0.5Ge0.5)2 (R ≡ La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y) and R(Pt0.5Ge0.5)2 (R ≡ Ce, Pr, Nd) where the palladium or platinum and germanium atoms are arranged at random on the copper sites. The tetragonal LaPtSi type, a ThSi2-type derivative, was found for RPtSi (R ≡ La, Ce, Pr, Nd, Sm, Gd), LaIrGe and LaPtGe. Finally the cubic LaIrSi type, an SrSi2-type derivative, was found for LaIrSi. The occurrence and structural features of these five structure types together with the tetragonal PbFCl type, an Fe2As-type derivative found earlier for RFeSi and RCoSi compounds, are discussed.
186 citations
TL;DR: Two systems of ternary transition metal phosphides with the ordered Fe(2)P-type hexagonal structure are reported, in which M can be Ti, Zr, or Hf.
Abstract: Two systems of ternary transition metal phosphides with the ordered Fe2P-type hexagonal structure are reported. They have the general formula MRuP and MOsP, in which M can be Ti, Zr, or Hf. An onset of the superconducting transition temperature as high as 13.0 K is reported for the ZrRuP compound.
80 citations
TL;DR: In this article, the crystal chemistry of ternary equiatomic phases of two transition metals and silicon or germanium is discussed, emphasizing differences in metal-metal bonding.
75 citations