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Semiconductor Physics, Quantum Electronics & Optoelectronics. 2006. V. 9, N 3. P. 070-078.
Spin-dependent transport in magnetic sandwiches
in the effective-mass approximation
1Institute for Magnetism, NAS of Ukraine, 36-B, Academician Vernadsky Blvd, 03142 Kyiv, Ukraine
Abstract. A theory describing a spin-dependent transport of electrons through a thin
metallic (or insulator) nonmagnetic layer sandwiched between two ferromagnets is
developed in the ballistic regime and current-perpendicular-to-plane (CPP) geometry.
The theory is based on the Landauer formalism and the transmission amplitude for the
electron Bloch waves with an arbitrary dispersion law travelling from one ferromagnet to
another through a nonmagnetic spacer (metallic or insulator). The semiclassical (nonoscillating) part of the magnetoresistance ratio for a metallic spacer is considered in the effective-mass approximation for the sandwich band structure. The parameters defining
the value of the giant magnetoresistance (GMR) effect are obtained. It is shown that the
electron specular scattering on the interfaces may be the cause for the CPP GMR effect.
The influence of the electronic structure on the CPP GMR effect has been studied
numerically in the effective-mass approximation.
Keywords: giant magnetoresistance effect, ballistic regime, effective-mass approximation.
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