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Transport properties of very thin films have been analysed using the layered potentials calculated by means of the ab initio method represented by the density functional theory (DFT) in the planar geometry for the nFe/3Cr/nFe films, where n is the number of monoatomic Fe layers, (1 ≤ n ≤ 8). We also take into consideration the values of the relaxation time and the effective mass of an electron in terms of the considered potentials. The matching conditions have been applied at the interface and the boundary conditions at the surface in order to determine, the contributions to the giant magnetoresistance (GMR) coming from the surface, interface, and inner layers. The surface roughness is introduced by means of the specularity factor Pσ defined in the spin-dependent terms responsible for the scattering of the electrons. Thus, the electron scattering at the outer surfaces depends on both spin orientations. The main result obtained in the paper is the evaluation that the surface contribution to GMR is very small in comparison with the effect of interface. [ABSTRACT FROM AUTHOR]

The transport properties of ultrathin metallic sandwich structures of Fe/Cr/Fe are studied as a function of magnetic layer thickness for the current in plane geometry (CIP). Taking into account the band structure obtained from density functional theory (DFT), we calculate basic physical properties such as Fermi energy and relaxation time for each magnetic and spacer layer. Next, using the Boltzmann formalism in its extended form, we obtain results for magnetoresistance (MR). In particular, we analyse the influence of effective mass parameterisation. [ABSTRACT FROM AUTHOR]

Abstract: Ab initio full-potential linearized augmented-plane-wave (FP-LAPW) method combined with the semiclassical Boltzmann formalism was employed to calculate the giant magnetoresistance ratio in the trilayers nFe/3Cr/nFe (). The present results emphasize the very important role of the ferromagnetic layer as well as the interfacial scattering and surface roughness on the giant magnetoresistance effect. [Copyright &y& Elsevier]

We consider the transport properties in magnetic multilayers for electronic current in the plane of the surfaces. The model is based on the effective s-band construction for the multilayer consisting of the metallic spacer and two ferromagnetic layers characterized by s-d coupling. We discuss the quasielectron spectrum in its effective mass approximation, with the perturbation taken into account by the effective potential, which also includes the interface contributions. We find the energy dispersion and the Fermi level for the effective s-band common for electrons in the whole sample. The results are equivalent in fact to those obtained within the Hood-Falicov model, but they seem to us much simpler and more transparent for their extensions and applications. [ABSTRACT FROM AUTHOR]

Abstract: The existence of enhanced or diminished interface magnetism of the trilayer structure is reported. The interfaces appearing in the structure A(n)/A c B1− c /B(p)/B1 c Ac/A(n) with n and p standing for the numbers of monoatomic layers of S A and S B spins, respectively, are considered in the form of binary alloys A c B1− c extended on two monoatomic planes mixed with an arbitrary concentration c for S A. In this structure, the temperature-dependent magnetization distribution across the trilayer we consider here leads to the non-homogeneity of the potential at the surface and interface layers, which now is different for different spin orientations. In consequence, GMR calculated by means of this local layered potential depends on the temperature. The numerical results for this dependence are presented in a particular case S A=1 and S B=1/2. [Copyright &y& Elsevier]