Dielectric permittivity of a magnetic fluid stratum in electric and magnetic fields.

V. M. Kozhevnikov - T. F. Morozova

NCSTU, Stavropol, 355029, Russia

Abstract
This work experimentally examines the electric capacitance and effective inductivity of the magnetic fluid (MF) layers with various concentrations under the influence of stationary electric and magnetic fields. The supply of constant polarizing voltage results in nonlinear change of the electric capacitance with the expressed maximum. In the zone of an electric intensity relevant to the maximum of electric capacitance, the orientation polarization of magnetic particles is most intensive and the process of structure formations is inconvertible (stable). The microscopic observations testify about various qualitative structural states dependent on the solid phase concentration, the distance between the electrodes and the rheology properties of the fluid–bottom system. At thermal gain of MF fluidity the orientation polarization increases. The dipole polarization attenuates at temperature decreasing. The superimposition of a magnetic field parallel to the electric one results in disappearing of the electric capacitance maximum, that at incoincidence of the directions of electrical and magnetic moments of magnetic particles reduces the orientation polarization caused by the electric field. The registered hysteresis of permittivity is similar to that of ferroelectric. Figs 5, Refs 8.