Superconductivity of Ternary Silicide with theAlB2-Type StructureSr(Ga0.37

Abstract

A ternary silicide Sr(Ga(0.37),Si(0.63))(2) was synthesized by a floating zone method. Electron diffraction and powder x-ray diffraction measurements indicate that the silicide has the AlB(2)-type structure with the lattice constants of a = 4.1427(6) A and c = 4.7998(9) A, where Si and Ga atoms are arranged in a chemically disordered honeycomb lattice and Sr atoms are inercalated between them. The silicide is isostructural with the high-temperature superconductor MgB(2) reported recently. Electrical resistivity and dc magnetization measurements revealed that it is a type-II superconductor with onset temperature of 3.5 K.

Electronic structure of YbGa1.15Si0.85and YbGaYamaoka1, Jarrige2, Tsujii3 et al. 2011Phys. Rev. BSelf Cite

“…Ternary silicides with the AlB 2 -type structure also showed superconductivity. [4][5][6][7][8] The superconductivity was also related to the lattice parameter within the layer rather than the interlayer spacing as shown in M AlSi (M =Ca, Sr, Ba). 9 Inelastic x-ray scattering for CaAlSi suggested soft-phonon-driven superconductivity, i. e. a conventional BCS superconductor in weak coupling regime.…”

Unconventional Behavior of Field-induced Quasiparticle Excitation in Ca(Al0.5Si0.5)2

“…β-ThSi 2 is known to be a superconductor with a critical temperature T c =2.41 K. 4 Above 16 GPa, CaSi 2 takes a AlB 2 -like structure, and it becomes superconducting with T c =14 K. 5 Recently, a new ternary silicide, Sr(Ga,Si) 2 , which also has the AlB 2 -type structure, was reported to be a superconductor with T c =3.4 K, 6 stimulating active investigation of analogous compounds. In this class of materials, ternary silicide Ca(Al 0.5 Si 0.5 ) 2 has the highest critical temperature T c =7.7 K.…”

Comparison of physical properties in BaAlSi and CaAlSi

“…Diffraction peaks of the single crystal do not contain impurity phase and they are much shaper than those of the polycrystal. No structural changes occur by annealing at 600 and 700 1C for 24 h. From the results, it is confirmed that BaAlSi single crystal is formed in the AlB 2 structure, same as MgB 2 and CaAlSi, and the lattice constants are a ¼ 4:292Å, c ¼ 5:154Å, almost the same as those of polycrystalline samples [5]. While CaAlSi has the superlattice in the (0,0,l)-and (1,0,l)-zone due to the periodic displacements of Al and Si along the c-axis [9], BaAlSi has no superlattice in all zones.…”

“…Since the discovery of MgB 2 [1], a lot of superconductors with AlB 2 structure have been developed [2][3][4][5][6]. Among them, CaAlSi is a superconductor with a relatively high superconducting transition temperature T c of 7.7 K [7].…”