Korniienko I. The form anisotropy effects of materials with antiferromagnetic order

The thesis is dedicated to the theoretical research of connection between a shape of a antiferromagnetic material sample and its magnetic properties, as well as to the creation of the theory of forming the magnetoelastic domains in multiferroics with antiferromagnetic ordering. The influence of a shape of compensated antiferromagnet of an "easy plane" type sample on the magnetic anisotropy and antiferromagnetic resonance spectrum has been studied. The phenomenological model describing the influence of a sample shape on the domain structure in multiferroic with simultaneous ferromagnetic and antiferromagnetic ordering has been built. On the basis of the developed model the field dependencies of magnetization were calculated. The calculated data and the presented experimental data were compared. The mechanism of a domain structure formation in a multiferroic with simultaneous ferroelectric and antiferromagnetic ordering has been suggested.