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arXiv · 1710.10250

Spin transfer and spin pumping in disordered normal metal-antiferromagnetic insulator systems

Sverre A. Gulbrandsen·Arne Brataas
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Abstract

We consider an antiferromagnetic insulator that is in contact with a metal. Spin accumulation in the metal can induce spin-transfer torques on the staggered field and on the magnetization in the antiferromagnet. These torques relate to spin pumping: the emission of spin currents into the metal by a precessing antiferromagnet. We investigate how the various components of the spin-transfer torque are affected by spin-independent disorder and spin-flip scattering in the metal. Spin-conserving disorder reduces the coupling between the spins in the antiferromagnet and the itinerant spins in the metal in a manner similar to Ohm's law. Spin-flip scattering leads to spin-memory loss with a reduced spin-transfer torque. We discuss the concept of a staggered spin current and argue that it is not a conserved quantity. Away from the interface, the staggered spin current varies around a zero mean in an irregular manner. A network model explains the rapid decay of the staggered spin current.

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Sverre A. Gulbrandsen, Arne Brataas. 2017-10-27. Spin transfer and spin pumping in disordered normal metal-antiferromagnetic insulator systems. https://doi.org/10.1103/physrevb.97.054409

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