Efeitos diamagneticos dependentes do Spin nas propriedades de transporte em multicamadas magneticas

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

Diamagnetic and spin-dependent Fermi surface effects are included in the calculation of the transport properties of metallic magnetic multilayers, to elucidate whether they can explain the Giant Magnetoresistance (GMR) effect observed in those systems. We consider that electrons in a multilayer sample, are subjected to a strong effective internal magnetic field, which has its origin in the large spin splitting in ferromagnets. The spin Fermi surfaces for majority and minority carriers are very different, yielding very different electronic orbit topologies for each spin. Scattering from the spacer could then couple orbits of different topologies at both sides of the interface between layers, in a way similar to magnetic breakdown phenomena. We calculate the galvanomagnetic tensors for both configurations, with ferromagnetic and antiferromagnetic couplings between magnetic layers, computing its difference. The transmission coefficient for scattering at the interface boundary is modelled to include magnetic contributions. The magnetoresistance tensor is obtained using the Chambers path integral approach, which is suited to calculate contributions of entangled networks of electronic orbits. Compensation-like effects enhance the magnetoresistance when the layers are coupled antiferromagnetically, and open orbits in particular directions yield interesting results. We suggest an interpretation of the magnetoresistance based in Fermi surface effects where diamagnetic effects have an important role

ASSUNTO(S)

superficies de efeitos galvanomagneticos teoria do transporte magnetoresistencia fermi filmes magneticos

ACESSO AO ARTIGO

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