Baranova K. Nonhomogeneous states in the phase transitions range of erbium orthoferrite

Object: phase transitions in monocrystal plates of erbium orthoferrite with different crystallographic orientations. Goal: ascertain nature of inhomogeneous states in the area of phase transitions on example of erbium orthoferrite. Methods: experimental investigations of inhomogeneous states in the area of phase transitions were established with devices based on magneto-optic Faraday effect. Two types of flowing cryostats were used. Energy spectrum was examined in a device with a flowing and flooded helium cryostat. Phenomenological and methodological approach were used to analyze results. Results: a composite method of nonhomogeneous states nature study is developed. It is the first time the nonhomogeneous states in the phase transitions region were investigated for stress-free samples and for samples with hard-magnetic layer. Investigation made it possible to conclude that this transition has magnetic nature and erbium plays crucial role in it. For the first time real multilayer models were proposed that explain nature of nonhomogeneous states reorganization in spin-reorientation area in erbium orthoferrite plates with surface magnetic hard layer. For the first time intermediate state in monocrystal erbium othoferrite plates was visualized at metamagnetic phase transition. A thermodynamic model of it's stabilization was proposed. Field of application: solid state physics, phase transitions, magnetism