Dynamics of thin-film spin-flip transistors with perpendicular source-drain magnetizations

A "spin-flip transistor" is a lateral spin valve consisting of ferromagnetic source-drain contacts to a thin-film normal-metal island with an electrically floating ferromagnetic base contact on top. We analyze the dc-current-driven magnetization dynamics of spin-flip transistors in which the source-drain contacts are magnetized perpendicularly to the device plane by magnetoelectronic circuit theory and the macrospin Landau-Lifshitz-Gilbert equation. Spin-flip scattering and spin pumping effects are taken into account. We find a steady-state rotation of the base magnetization at GHz frequencies that is tunable by the source-drain bias. We discuss the advantages of the lateral structure for high-frequency generation and actuation of nanomechanical systems over recently proposed nanopillar structures.