Investigation of the degree of occupancy of 3d and 4s bands of 3d metals and their alloys on the basis of a four-band model

A four-band model is used as the basis for obtaining relationships suitable for the calculation of a number of the s electrons in 3d metals and their alloys. The results are given of calculations of this number in Fe, Co, Ni, and Cu, and their Fe-Co, Co-Ni, and Ni-Cu alloys. A quantitative agreement is found between the number of the s electrons and the available published data. The results indicate the presence of vacant states in the d band of Cu and in the d subband of Ni, which is usually assumed to be completely filled. The results demonstrate shortcomings of the four-band model in explaining the magnitude of the normal Hall coefficient of Co and of Fe-Co, Co-Ni, and Ni-Cu alloys.