Supercondutivity of Nb-Ta-Ti-Zr-Hf high entropy alloy polycrystalline and amorphous thin films

Abstract: We studied the superconductivity of high-entropy Hf-Nb-Ta-Ti-Zr alloy films affected by structural order. While films deposited from the same target on a substrate with a room temperature are amorphous, and if superconducting, only at temperatures below 1.9 K, films deposited on a substrate with a temperature of 740 $^o$C and 630 $^o$C are superconducting with a critical temperature of 6.61 K and 6.63 K, respectively. The observed effect of structural order on superconductivity can be explained by the theory of superconductivity in strongly bound amorphous materials recently published by Baggioli et al.