Thermoelectrical manipulation of nanomagnets - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate

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Abstract: We investigate the interplay between the thermodynamic properties andspin-dependent transport in a mesoscopic device based on a magnetic multilayerF-f-F, in which two strongly ferromagnetic layers F are exchange-coupledthrough a weakly ferromagnetic spacer f with the Curie temperature in thevicinity of room temperature. We show theoretically that the Joule heatingproduced by the spin-dependent current allows a spin-thermo-electronic controlof the ferromagnetic-to-paramagnetic f-N transition in the spacer and,thereby, of the relative orientation of the outer F-layers in the devicespin-thermo-electric manipulation of nanomagnets. Supporting experimentalevidence of such thermally controlled switching from parallel to antiparallelmagnetization orientations in F-fN-F sandwiches is presented. Furthermore, weshow theoretically that local Joule heating due to a high concentration ofcurrent in a magnetic point contact or a nanopillar can be used to reversiblydrive the weakly ferromagnetic spacer through its Curie point and therebyexchange couple and decouple the two strongly ferromagnetic F-layers. For thedevices designed to have an antiparallel ground state above the Curie point ofthe spacer, the associated spin-thermionic parallel-to-antiparallel switchingcauses magneto-resistance oscillations whose frequency can be controlled byproper biasing from essentially DC to GHz. We discuss in detail an experimentalrealization of a device that can operate as a thermo-magneto-resistive switchor oscillator.

Author: A.M. Kadigrobov, S. Andersson, D. Radic, R.I. Shekhter, M. Jonson, V. Korenivski


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