Simulation of the interband s–d and intraband s–s electron–phonon contributions to the temperature dependence of the electrical resistivity in Fe/Cr multilayers

Abstract

High-resolution electrical resistivity (rho, d rho/dT) measurements were performed in three series of [Fe-30 Cr-Angstrom(t) (Angstrom)] multilayers in the temperature range 15-300 K, with an applied magnetic saturation field (7.5 kOe). The samples were deposited by molecular beam epitaxy on MgO substrates and by sputtering on MgO and Si substrates. For T < 50 K the ideal resistivity follows rho(i) = beta T-3, indicating the dominance of phonon-assisted interband s-d scattering in this temperature range. For T >150 K the resistivity attains the classical regime with rho proportional to T. To simulate the observed rho(i)(T) we have used a model that takes into account intraband s-s and interband s-d electron-phonon scattering, written as rho(sd) = A X f(1)(T) and rho(ss) = B X f(2)(T), where f(1) and f(2) are functions only of the temperature, A and B are sample-dependent constants and rho(i) = rho(sd) + rho(ss). The model predicts that rho(i) proportional to T-3 at low temperatures and rho(i) proportional to T at high temperatures as observed in our multilayers. The experimental curves of rho(i) and d rho/dT are well reproduced in the whole temperature range (15-300 K) and from the fits to these curves A and B are determined for each sample. By plotting B vs A we find that each point from all the multilayers falls in a straight line indicating that B is proportional to A. The simulated resistivity thus predicts that rho(i) = beta f(T) where f(T) = alpha(1) x f(1)(T) + alpha(2) x f(2)(T) is a function only of the temperature, as observed experimentally.