Charge pumping and the colored thermal voltage noise in spin valves

Spin pumping by a moving magnetization gives rise to an electric voltage over a spin valve. Thermal fluctuations of the magnetization manifest themselves as increased thermal voltage noise with absorption lines at the ferromagnetic resonance frequency and/or zero frequency. The effect depends on the magnetization configuration and can be of the...

Spin-transfer torque in magnetic tunnel junctions: Scattering theory

We study the bias-dependent spin-transfer torque in magnetic tunnel junctions in the Stoner model by scattering theory. We show that the in-plane (Slonczewski type) torque vanishes and subsequently reverses its direction when the bias voltage becomes larger or the barrier wider than material and device-dependent critical values. We are able to...

Charge pumping in magnetic tunnel junctions: Scattering theory

We study theoretically the charge transport pumped by magnetization dynamics through epitaxial FIF and FNIF magnetic tunnel junctions (F, ferromagnet; I, insulator; N, normal metal). We predict a small but measurable dc pumping voltage under ferromagnetic resonance conditions for collinear magnetization configurations, which may change sign as a...