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Spin Dynamics in a Tunnel Junction between Ferromagnets

J. Fransson·Jian-Xin Zhu
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Abstract

The dynamics of a single spin embedded in the tunnel junction (quantum point contact) between ferromagnets is addressed. Using the Keldysh technique, we derive a quantum Langevin equation. As a consequence of the spin-polarization in the leads, the spin displays a rich and unusual dynamics. Parallel configured and equally strong magnetic moments in the leads yield an ordinary spin precession with a Larmor frequency given by the effective magnetic field. Unequal and/or non-parallel configured magnetization, however, causes nutation of the spin in addition to the precession. Our predictions may be directly tested for macroscopic spin clusters.

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J. Fransson, Jian-Xin Zhu. 2007-12-03. Spin Dynamics in a Tunnel Junction between Ferromagnets. https://doi.org/10.1088/1367-2630%2F10%2F1%2F013017

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