Superconductivity in Mo5SiB2

In the Mo–Si binary system, Mo5Si3 crystallizes in the W5Si3 (T1 phase) structure type. However, when boron replaces silicon in this compound, a structural transition occurs from the W5Si3 prototype structure to the Cr5B3 prototype structure (T2 phase) at the composition Mo5SiB2. Mo5SiB2 has received much attention in the literature as a candidate for structural application in high-temperature turbines, but its electronic and magnetic behavior has not been explored. In this work, we show that Mo5SiB2 is a bulk superconducting material with critical temperature close to 5.8 K. The specific-heat, resistivity and magnetization measurements reveal that this material is a conventional type II BCS superconductor.