Nb对C-15结构V2(HfZr)系列的超导转变温度的影响

本文中研究了C-15结构V₂Hf_1-xNb_x,V₂Zr_1-xNb_x和V₂Hf_0.5Zr_0.5-xNb_x系列的超导转变温度T_c与Nb合量x的关系,发现V₂Zr,V₂Hf加Nb后与V₂Hf_0.5Zr_0.5加Nb后性能显著不同。测定了V₂Zr,V₂Hf和V₂Hf_0.5Zr_0.5的X射线光电子能谱。结果表明,当Hf原子和Zr原子共存于AB₂化合物的A位上时,发生了一种增强原子间相互作用的新的电荷转移。这个事实支持由角动量分波表象能带论方法分析电声耦合超导原理的结果对四元V₂(HfZrNb)系列的超导行为提出的一种可能解释:4d-5d原子配位可能有助于提高4d导带的杂化程度,从而有利于提高超导T_c。 关键词：

THE EFFECT OF Nb ON SUPERCONDUCTING Tc OF C-15 V2 (HfZr)

The superconducting transition temperatures T_c of systems V₂Hf_1-xNb_x,V₂Zr_1-xNb_x and V₂Hf_0.5Zr_0.5-xNb_x were studied. We found that Nb content influences SC T_c of V₂Hf_0.5Zr_0.5-xNb_x in a different way from that of V₂Hf_1-xNb_x and V₂Zr_1-xNb_x. X-ray photoelectron spectroscopy of V₂Zr, V₂Hf and V₂Hf_0.5Zr_0.5 showed that the coexistence of Zr and Hf atoms in A sites of AB₂ compounds results in a new type of electron density transfer enhancing the interaction of atoms. This fact supports the following explanation to T_c behavior: 4d-5d coordination of V₂(HfZr) may favor the hybridization of 4d conduction band thus causing higher T_c.