Magnetoelectric effect in Mn1-xCoxS

Dielectric permittivity measurements depending on magnetic and electric fields at various frequencies in the temperature limits 80…300 К are carried out. The change in the dielectric permittivity is found in the external magnetic field at the temperature associated with creation of spontaneous magnetic moment at T1 ~ 120 K and at T2 ~ 230 K. The nonlinear behavior of dielectric permittivity similarly to superparamagnetic versus external electric field at T > 230 K is revealed. These effects are explained in terms of formation of bounded electron-phonon state having incommensurate dipole ordering and ferromagnetic order of orbital magnetic moments.