Nb对C-15相V2Zr和V2(HfZr)系列声子性能的影响

本文用中子飞行时间方法对C-15相的超导物质V₂Zr,V₂Zr_0.95Nb_0.05及V₂Hf_0.5Zr_0.5,V₂Hf_0.5Zr_0.3Nb_0.2的热中子非弹性散射谱作了测量,发现Nb的添加对V₂Zr和V₂Hf_{0.5 关键词：}

THE EFFECT OF Nb ON PHONONS OF SUPERCONDUCTORS C-15 V2Zr AND V2(HfZr)

Inelastic neutron scattering spectra from superconducting material C-15 V₂Zr, V₂Zr_0.95Nb_0.05 and V₂Hf_0.5Zr_0.5,V₂Hf_0.5Zr_0.3Nb_0.2 were measured by neutron time-of-flight method. It was found that the additional content of Nb influenced the superconducting transition temperature T_c and phonon frequencies of V₂Zr_1-xNb_x in a way different from that of V₂Hf_0.5Zr_0.5-xNb_x. The T_c increases and the phonon frequencies "soften" with increasing x for the former, while the Tc slightly decreases and the phonon frequencies "harden" for the latter. The result that the phonon frequencies of V₂Zr_0.95Nb_0.05 are softer than that of V₂Zr is somewhat in contradiction with the previous results, which show that the magnetic susceptibilities decrease and the geometric mean phonon frequencies increase. The result that the phonon frequencies of V₂Hf_0.5Zr_0.3Nb_0.2 are harder than that of V₂Hf_0.5Zr_0.5 can be considered as the result of hybridization of conduction band, which is studied for close-packed compounds by means of LMTO (linear combination of muffin-tin orbitals) method.