Thermoelectric power and electronic structure of dilute alloys of nickel and cobalt with d transition elements

We present new measurements of thermoelectric power for nickel and cobalt dilute alloys with d transition elements in two temperature ranges: from 1.3 to 4.2 K and from 77 to 300 K. We analyse the measurements at room temperature in a two-band conduction model and deduce the thermopowers associated with the matrix ( S mσ ) and with the impurities ( S oσ ) in each sub-band σ. The results obtained for the impurity thermoelectric power confirm the model of electronic structure suggested for this alloy from magnetization and resistivity measurements; this model is characterized by the occurrence of a virtual bound state s upward arrow d upward arrow at the Fermi level when the charge difference between the matrix and the impurity is large enough. From the values of impurity thermoelectric power in the s upward arrow sub-band, we deduce the position and the width of the virtual bound state.