Superconductivity in MgPtSi: An orthorhombic variant of MgB2

A ternary compound, MgPtSi, was synthesized by solid-state reaction. An examination of the compound by powder X-ray diffraction revealed that it crystallizes in the orthorhombic TiNiSi-type structure with the Pnma space group. The structure comprises alternately stacked layers of Mg and PtSi honeycomb network, which is reminiscent of MgB2, and the buckling of the honeycomb network causes orthorhombic distortion. Electrical and magnetic studies revealed that MgPtSi exhibited superconductivity with a transition temperature of 2.5 K. However, its isostructural compounds, namely, MgRhSi and MgIrSi, were not found to exhibit superconductivity.