Nguyen, Quang Anh (2009) Contribution à l'étude de la diffusion et du transfert de spin à une interface ferromagnétique-normal mesurés sur des nanofils électrodéposés. PhD thesis Physique, LSI - Ecole Polytechnique, EP/X p.141.

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Abstract

This work is part of a study of the transfer of spin measured on a single domain ferromagnetic. The ferromagnetic monodomain is a single nanowire of Ni or Co electrodeposited in a nanoporous matrix.



The study aims to give prominence to the properties of spin relaxation of conduction electrons at the interface between the ferromagnetic domain and the normal contact, in terms of the interaction between the spins of conduction electrons and the ferromagnetic order parameter. This means, with the last study, to underline that the diffusive spin-transfer effect would be a consequence of this relaxation.



In a first approach, an anisotropic spin accumulation, involving the interaction $s-d$ (or spin-orbit interaction), is studied through the thermoelectric power (TEP). The spin-dependent TEP effect is proved, which is restricted to the interface and is anisotropic. This contribution is interpreted as the effect of the spin accumulation produced by a $s-d$ relaxation.

résultats confortent une approche diffusive du transfert de spin.



In a second study, the spin transfer effect is studied through the thermal susceptibility of anisotropy magnetoresistance $dR/dT$. It shows that the susceptibility is due to the susceptibility of the magnetization $dM/dT$. Fluctuations in the magnetization generated by the injection of strong current are measured in terms of entropy variation. A variation of $60\%$ is measured with a current intensity of about $10^{7}A/cm^{2}$. These results support the diffusive spin transfer approach.

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