Resonance effect of a radio frequency field on the rotational diffusion of magnetic nanoparticles

Abstract

The work investigates the rotational-stochastic dynamics (rotational diffusion) of magnetic suspension nanoparticles, created by random collisions of nanoparticles with liquid molecules. The flow of root-mean-square fluctuations of rotational motion acquires the character of periodic motion at large times. The frequency of this motion is due to the cyclicity of the angular variables of the nanoparticles and is proportional to the Brownian relaxation rate. It is shown that with the help of a weak radio-frequency field resonant with this periodic motion, it is possible to increase the average rotation speed. It is also shown that by selecting the parameters of the resonant field, it is possible to achieve a stationary deviation of the magnetic moments of nanoparticles by the desired angle.