Structural evolution and superconductivity tuned by valence electron concentration in the Nb-Mo-Re-Ru-Rh high-entropy alloys  

作　　者：Bin Liu Jifeng Wu Yanwei Cui Qjnqing Zhu Guorui Xiao Siqi Wu Guang-han Cao Zhi Ren 

机构地区：[1]School of Science,Westlake University,18 Shilongshan Road,Hangzhou,310064,China [2]Institute of Natural Sciences,Westlake Institute for Advanced Study,Hangzhou,310064,China [3]Department of Physics,Fudan University,Shanghai,200433,China [4]Department of Physics,Zhejiang University,Hangzhou,310027,China

出　　处：《Journal of Materials Science & Technology》2021年第26期11-17,共7页材料科学技术（英文版）

基　　金：financial support by the foundation of Westlake University;supported by the National Key Research Development Program of China(No.2017YFA0303002)。

摘　　要：The crystal structure and physical properties of Nb_(25)Mo_(5+x)Re_(35)Ru_(25-x)Rh_(10)(0≤x≤10)and Nb_(5)Mo_(35-y)Re_(15+y)Ru_(35)Rh_(10)(0≤y≤15)high-entropy alloys(HEAs)have been studied by X-ray diffraction,electrical resistivity,magnetic susceptibility,and specific heat measurements.The results show that the former HEAs with valence electron concentration(VEC)values of 6.7-6.9 crystallize in a noncentrosymmetric cubicα-Mn structure,while the latter ones with VEC values of 7.1-7.25 adopt a centrosymmetric hexagonal close-packed(hcp)structure.Despite different structures,both series of HEAs are found to be bulk superconductors with a full energy gap,and the superconducting transition temperature Tc tends to decrease with the increase of VEC.Nevertheless,the Tc values of the hcp-type HEAs are higher than those of theα-Mn-type ones,likely due to a stronger electron phonon coupling.Furthermore,we show that VEC and electronegativity difference are two key parameters to control the stability ofα-Mn and hcp-type HEAs.These results not only are helpful for the design of such HEAs,but also represent the first realization of structurally different HEA superconductors without changing the constituent elements.

关 键 词：High-entropy alloys Hcp toα-Mn structural evolution Superconducting properties Valence electron concentration Electronegativity difference 

分 类 号：TG139[一般工业技术—材料科学与工程]