Resistivity and magnetoresistance anisotropy associated with s, p impurities in ferromagnetic Ni and Co

Abstract

The authors have measured the electrical resistivity between 4.2K and 300K, and the longitudinal and transverse magnetoresistance at 4.2K, of several dilute Co and Ni based alloys containing various s, p impurities such as Sn and Sb. The deviations from Matthiessen's rule (DMR) derived from the resistivity data have been analysed in terms of the two current model of Campbell et al. (1968) and values for alpha (the ratio of spin up to spin down resistivities at the impurity site), mu (the same ratio at host sites) and D (the coefficient of the spin mixing term) estimated. The bulk of these data yield alpha approximately=1 for these impurities, as expected on the basis of a simple virtual bound state picture. The magnetoresistance data also yield values of alpha close to 1, but there are systematic differences between experiment and the predictions of the two current model.