Superconductivity of high-entropy-alloy-type transition-metal zirconide (Fe,Co,Ni,Cu,Ga)Zr2

Abstract

We synthesized a new high-entropy-alloy-type (HEA-type) superconductor (Fe,Co,Ni,Cu,Ga)Zr2 with a Tc of 2.9 K. The EDX analyses revealed that the actual composition of the transition-metal site (Tr-site) is Tr = Fe0.18Co0.18Ni0.16Cu0.25Ga0.23, which gives the configurational entropy of mixing ΔSmix = 1.60R for the Tr site. Neutron powder diffraction revealed that the sample has a tetragonal CuAl2-type (space group: #140). The lattice constant of a monotonically decreases with decreasing temperature, but the lattice constant of c does not exhibit a clear shrinkage. Isotropic displacement parameter for both the Tr and Zr sites are large, which is probably caused by the HEA-type Tr site. The small temperature dependences of Uiso for both sites also indicate the presence of the local structural disorder in (Fe,Co,Ni,Cu,Ga)Zr2. From electrical resistivity, magnetic susceptibility, and specific heat measurements, bulk superconductivity was confirmed.

arXiv comment6 pages, 5 figures

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Cited by in corpus (4)

• Sign change in c-axis thermal expansion and lattice collapse by Ni substitution in Co1-xNixZr2 superconductors
• Local distortions of the crystal structure and their influence on the electronic structure and superconductivity of the high-entropy alloy (TaNb)0.67(HfZrTi)0.33
• Axis thermal expansion switching in transition-metal zirconides TrZr2 by tuning the c/a ratio
• Uniaxial negative thermal expansion in an orthorhombic superconductor CoZr3