Resonance retardation of a domain wall by Winter magnons in orthoferrites

Supersonic domain-wall dynamics is investigated in wafer samples of YFeO3 having thicknesses of 10 mu m, 35 mu m, 40 mu m, 120 mu m, and 125 mu m, prepared by different methods, and in a mm, mm, EuFeO3 sample of thickness 60 mu m at liquid-nitrogen temperature. Relations are established for the occurrence of nonlinear segments in the form of constant-wall-velocity intervals in the dependence of the wall velocity on the pulsed magnetic field amplitude. Qualitative agreement is obtained between the experimental data and calculated values of the velocities and widths of the constant-velocity intervals, on the assumption that the mechanism of resonance retardation of the domain walls by parametrically excited Winter (wall as opposed to bulk) magnons is operative at supersonic velocities. (C) 1998 American Institute of Physics. [S1063-7834(98)01909-1].