Specific features of spontaneous reorientation of the magnetic moment in a single-crystal thin plate of the iron garnet Tb0.2Y2.8Fe5O12

The Faraday effect, light scattering, and changes in the domain structure of a single-crystal thin plate of the iron garnet Tb0.2Y2.8Fe5O12 cut parallel to the (110) crystallographic plane have been experimentally investigated in the temperature range of the spontaneous magnetic orientational phase transition. It has been established that the transformation of the domain structure of the studied sample due to the orientational phase transition is accompanied by a significant temperature hysteresis. A model of the spontaneous reorientation of the magnetic moment vector of the crystal has been proposed by analyzing the results of visual observations of the domain structure and the temperature dependences of the Faraday effect and light scattering. In the proposed model, preference is given to the spin wave mechanism of nucleation of domains of the equilibrium magnetic phases.