Magneto-Optical Method for Observing the Phases of Magnetic Ordering in Rare Earth Ferrite Films Using a Compensating Point

For the purpose of studying the noncollinear phase in ferrimagnetic films with a magnetic compensation point, a technique has been developed and an experimental setup has been fabricated for observing phase transitions in ferrimagnetic films using magneto-optical contrast. The unique feature of the setup with a superconducting magnet is the presence of a controllable lateral temperature gradient that allows simultaneous observation of various phase states in ferrimagnetic films in the range of magnetic fields and temperatures using the magneto-optical method. Using the developed setup, zones of different magnetic ordering were observed for rare earth garnet ferrites in the range of magnetic fields from 0 to 10 T and temperatures from 150 to 400 K. The lateral temperature gradient in the film plane could be varied from 0 to 12 K. Different phases of the first-order spin-reorientation transition were observed in films with a composition of (BiYGd)₃(FeGa)₅O₁₂ using this technique.