Superconductivity of MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga), ternary silicides with the AlB2-type structure

TL;DR

This study reports the synthesis and characterization of ternary silicides with AlB2-type structure, revealing superconductivity in some compounds with critical temperatures up to 5.1 K.

Contribution

It introduces new superconducting ternary silicides with AlB2-type structure and provides their synthesis, structural analysis, and superconducting properties.

Findings

Sr(Al0.5, Si0.5)2 is superconducting at 4.2 K.

Ba(Al0.5, Si0.5)2 is not superconducting above 2.0 K.

Sr(Ga0.5, Si0.5)2 and Ba(Ga0.5, Si0.5)2 are superconductors with TCs of 5.1 K and 3.3 K.

Abstract

Ternary silicides MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga) were prepared by Ar arc melting. Powder X-ray diffraction indicates that they have the AlB2-type structure, in which Si and MII atoms are arranged in honeycomb layers and MI atoms are intercalated between them. Electrical resistivity and dc magnetization measurements revealed that Sr(Al0.5, Si0.5)2 is superconductive, with a critical temperature for superconductivity (TC) of 4.2 K, while Ba(Al0.5, Si0.5)2 is not at temperatures ranging above 2.0 K. Sr(Ga0.5, Si0.5)2 and Ba(Ga0.5, Si0.5)2 are also superconductors, with TCs of 5.1 and 3.3 K, respectively.