Spatial resonance in ferromagnetics

Phenomenological Landau theory is used to study an interaction between structural and magnetic subsystems in a crystal in the vicinity of phase-transition lines. It is demonstrated that the twist-induced severe plastic deformation results in a forced onset of inhomogeneous distribution in the magnetic subsystem. A nonsinusoidal spatial modulation of magnetic and structural order parameter moduli is found to arise near the lines of magnetic or structural phase transition. The obtained results permit to construct various distributions of ferromagnetic vector in crystals under twist-induced severe plastic deformation.