Siryuk J. Features of domain structures in ferrite-garnet films with compensation point and spin reorientation

Еhe equilibrium domain structure (DS) features under varying temperature and/or magnetic field in ferrite-garnet films have been investigated in the 90-500 K temperature range. It has been revealed that in regular domain structures (bubble domain lattice and honeycombed DS), the spontaneous first-order phase transitions occur with both the conservation of particle (domain) number and decrease in particle number. The character of phase transitions is defined by the magnetostatic pressure of the domain structures as well as by the sign of a change in characteristic length of the film. Mechanism of the spin-reorientation phase transition (SRPT) in the films with mixed anisotropy has been investigated. The phase transitions occur in domain boundaries and, as a consequence, inside the domain. It has been determined that the spiral domains, that contain a large number of turns, can be stabilized by the surrounding BD lattice as well as by the surrounding of another spiral domains (spiral-domain lattice). Phase transitions in the coexisting domain structures are interrelated. Spiral domain nucleates from dumbbells domain. As a result, the mechanism, regularities and features of phase transitions occurring in the domain structure of ferrite-garnet films under temperature and/or magnetic field variation have been determined; and, as a consequence, it is shown that it is possible to simulate phase transitions in solids.The new laws of phase transitions in domain structures can be applied at development of a new element base for creation of selective optical filters, in magnetooptics, spintronics and other.