非晶Nb-Ni合金的电子结构及其磁性和超导电性

用紫外光电子能谱(UPS)研究了非晶Nb_100-xNi_x(x=65,59.8,56.4)合金的电子结构,得到Nb-Ni合金的费密能级位于态密度曲线极小附近。从电子结构说明了Nb-Ni合金中存在双居里点现象的原因。对非晶Nb-Ni合金的电子结构分析指出:能量接近的两个d带杂化结果致使在费密面附近形成新的杂化带,杂化程度与两元素的价差有关。电荷转移引起带峰移动。费密能级态密度中应包含两部分的贡献:有利于磁性的3d电子态和有利于超导的4d电子态。费密能级处这两部分的分 关键词：

THE ELECTRON STRUCTURE, MAGNETISM AND SUPERCONDUCTIVITY OF AMORPHOUS Nb-Ni ALLOYS

The electron structures of amorphous Nb_100-xNi_x (x= 65, 59.8, 56.4) alloys are studied by means of UV-Photoelectron spectroscopy (UPS). It is found that the position of the Fermi level is located near the minimum of the density of states, which explains the double Curie-point phenomena in Nb-Ni alloys. Analysing the electron structure of Nb-Ni alloys, it is pointed out that the hybridization of two d-bands with energies close to each other may form a new hybridizated band near E_F and the hybridization is related to the valence difference. The charge transfer makes the peaks of bands shifting. The density of states of T_E-T_L. alloys at E_F should include two parts of contributions, i.e., that from 3d electron stsates, which is of advantage to magnetism, and that from 4d electron states, being of advantage to superconductivity. Different ratio of these contributions at Er influences the magnetism and superconductivity of the alloys greatly. The coexistence of localized magnetic moments and superconductivity has also been discussed.