THEORY OF MAGNETORESISTANCE IN FILMS OF DILUTE MAGNETIC ALLOYS

摘要

Recently, two attempts have been made to explain the size dependence of the Kondo effect: (ⅰ) static disorder proposed by Martin, Wan and Phillips, and (ⅱ) surface spin anisotropy for magnetic impurities due to spin-orbit interaction between the nonmagnetic host atoms and electrons. These two suggestions can be applied in the opposite limits, namely in the dirty and ballistic regions. According to the theory (ⅱ), if the normal vector of the surface is n, then the anisotropy energy is H_a = K_d(nS)~2, where S is the spin operator of the impurity spin and K_d is the strength of the anisotropy which depends inversely on the distance d of the impurity measured from the surface.