Superconductivity of the new medium-entropy alloy V4Ti2W with a body-centered cubic structure

Abstract

Medium- and high-entropy alloy (MEA and HEA) superconductors have attracted considerable interest since their discovery. This paper reports the superconducting properties of ternary tungsten-containing MEA V4Ti2W for the first time. V4Ti2W is a type II superconductor with a body-centered cubic (BCC) structure. This structure belongs to the space group Im3̅m (No. 229) with the cell parameters a= b = c = 3.10673(14) Å. Experimental results of resistivity, magnetization, and heat capacity indicate that the superconducting transition temperature of the MEA V4Ti2W is roughly 5.0 K. The critical magnetic fields at the upper and lower ends are 9.93(2) T and 40.7(3) mT, respectively. Interestingly, few BCC MEA superconductors with VEC greater than 4.8 have been found. The addition of tungsten leads to a VEC of 4.83 e/a for V4Ti2W, which is rarely higher than the 4.8 value. Adding tungsten element expands the variety of MEA alloys, which may improve the microstructure and mechanical properties of materials and even superconducting properties. This material could potentially offer a new platform for the investigation of innovative MEA and HEA superconductors.