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

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Abstract
High-resolution electrical resistivity (ρ,dρ/dT) measurements were performed in three series of [Fe30 ÅCrt Å] 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 T150 K the resistivity attains the classical regime with ρ∝T. To simulate the observed ρi(T) we have used a model that takes into account intraband s–s and interband s–d electron–phonon scattering, written as ρsd=A×f1(T) and ρss=B×f2(T), where f1 and f2 are functions only of the temperature, A and B are sample-dependent constants and ρi=ρsd+ρss. The model predicts that ρi∝T3 at low temperatures and ρi∝T at high temperatures as observed in our multilayers. The experimental curves of ρi and dρ/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 ρi=βf(T) where f(T)=α1×f1(T)+α2×f2(T) is a function only of the temperature, as observed experimentally.