Anisotropic and controllable Gilbert-Bloch dissipation in spin valves

Abstract

Spin valves form a key building block in a wide range of spintronic concepts and devices from magnetoresistive read heads to spin-transfer-torque oscillators. We elucidate the dependence of the magnetic damping in the free layer on the angle its equilibrium magnetization makes with that in the fixed layer. The spin pumping-mediated damping is anisotropic and tensorial, with Gilbert- and Bloch-like terms. Our investigation reveals a mechanism for tuning the free layer damping in-situ from negligible to a large value via the orientation of fixed layer magnetization, especially when the magnets are electrically insulating. Furthermore, we expect the Bloch contribution that emerges from the longitudinal spin accumulation in the non-magnetic spacer to play an important role in a wide range of other phenomena in spin valves.

References in corpus (7)

• Spin Transfer Torques
• Spin Seebeck insulator
• Theory of spin Hall magnetoresistance
• Observation of the spin Nernst effect
• Noninteger-spin magnonic excitations in untextured magnets
• Enhancement of the Gilbert damping constant due to spin pumping in noncollinear ferromagnet/nonmagnet/ferromagnet trilayer systems
• Spin relaxation in multilayers with synthetic ferrimagnets

Cited by in corpus (1)

• Angle resolved relaxation of spin currents by antiferromagnets in spin valves