Superconductivity in (TaNb)1–x(ZrHfTi)xMoy high-entropy alloy films

Abstract

Superconducting high entropy alloys (HEAs) are a novel class of superconductors, with applications for electronic devices. Here, we investigated the effect of Mo alloying on superconducting properties of high entropy films with the composition (TaNb)1–x(ZrHfTi)xMoy. For near-equimolar composition, the crystalline HEAs grains are transformed into amorphous aggregations with a size in a few nanometer scale, forming a crystal/glass nanocomposite. In both crystalline and amorphous HEAs, the constituent atoms exhibit a homogeneous random distribution. The entropy-affected phase formations suppress the superconducting transitions in HEAs, which broadens the normal-to-superconducting transition regime and suppresses the zero-resistivity critical temperature to a lower constant value of approximately 2.9 K.