Effect of current on magnetization oscillations in the ferromagnet-antiferromagnet junction

Abstract

The effect of spin polarized current on the steady state magnetization and oscillations of antifer romagnet magnetization in a ferromagnetic-antiferromagnetic magnetic junction is analyzed. The mac rospin approximation is generalized to describe antiferromagnets. The canted configuration of the antiferro magnet and the resultant magnetic moment are produced by the application of an external magnetic field. The resonance frequency, damping, and threshold current density corresponding to the emergence of insta bility are calculated. The possibility of generating weakly damped magnetization oscillations in the terahertz range is demonstrated. The effect of fluctuations on the canted configuration of the antiferromagnet is dis cussed.

sd-Exchange electron spin resonance in a ferromagnetic metal

“…The amplitude of precession is maximal at the res onance frequency (10) The Q factor of the system is given by the expression (11) The power absorbed in unit volume has the form (12) where the angular brackets stand for time averaging. We have (13) where θ is the angle between the vectors M and H 0 .…”

“…These data stimulate interest in systems resonant in the terahertz range that can be used as receivers of terahertz radiation. A ferromag net-antiferromagnet magnetic transition whose high resonance frequency is due to the strong exchange interaction between the magnetic sublattices of the antiferromagnet is an example [10,11].…”

Current-induced resonance in a ferromagnet - antiferromagnet junction

“…In this approximation, the layer magnetization is supposed to be uniform in thickness, while the spin current through the interface is taking into account by means of additional terms in the equations (see Refs. [25,13] for details). A simplest AFM model is considered with two collinear equivalent sublattices with equal magnetizations, |M1| = |M2| = M0.…”

“…The Landau-Lifshitz-Gilbert equations for the AFM layer in the presence of spin-polarized current and high frequency magnetic field take the following form (see detailed derivation in Ref. [13]):…”

“…The current effect on the spectrum and damping of the magnetization oscillation in antiferromagnets was studied in Refs. [13,14]. It was shown that the spin-polarized current effect leads to decrease in damping and to instability of the antiparallel configuration with switching to parallel one.…”