5 research outputs found
Magnetoelastic coupling and possibility of spintronic electromagnetomechanical effects
Nanoelectromagnetomechanical systems (NEMMS) open up a new path for the development of high speed
autonomous nanoresonators and signal generators that could be used as actuators, for information processing, as
elements of quantum computers etc. Those NEMMS that include ferromagnetic layers could be controlled by the
electric current due to effects related with spin transfer. In the present paper we discuss another situation when
the current-controlled behavior of nanorod that includes an antiferro- (instead of one of ferro-) magnetic layer.
We argue that in this case ac spin-polarized current can also induce resonant coupled magnetomechanical oscillations
and produce an oscillating magnetization of antiferromagnetic (AFM) layer. These effects are caused by
i) spin-transfer torque exerted to AFM at the interface with nonmagnetic spacer and by ii) the effective magnetic
field produced by the spin-polarized free electrons due to sd-exchange. The described nanorod with an AFM
layer can find an application in magnetometry and as a current-controlled high-frequency mechanical oscillator
Peculiarities of the stochastic motion in antiferromagnetic nanoparticles
Antiferromagnetic (AFM) materials are widely used in spintronic devices as
passive elements (for stabilization of ferromangetic layers) and as active
elements (for information coding). In both cases switching between the
different AFM states depends in a great extent from the environmental noise. In
the present paper we derive the stochastic Langevin equations for an AFM vector
and corresponding Fokker-Planck equation for distribution function in the phase
space of generalised coordinate and momentum. Thermal noise is modeled by a
random delta-correlated magnetic field that interacts with the dynamic
magnetisation of AFM particle. We analyse in details a particular case of the
collinear compensated AFM in the presence of spin-polarised current. The energy
distribution function for normal modes in the vicinity of two equilibrium
states (static and stationary) in sub- and super-critical regimes is found. It
is shown that the noise-induced dynamics of AFM vector has pecuilarities
compared to that of magnetisation vector in ferromagnets.Comment: Submitted to EPJ ST, presented at the 4-th Conference on Statistical
Physics, Lviv, Ukraine, 201