Nonlinear variation with applied field of the mobility of magnetic domain walls in yttrium orthoferrite

Abstract

The mobilities of the magnetic domain wall in yttrium orthoferrite, YFeO₃, as grown by the flux method were investigated by the bubble collapse method. The observed relationship between the domain wall velocity and the drive pulse field was nonlinear, having the following features: (i) an initial low-mobility slope (similar 25 cm s⁻¹ Oe⁻¹); (ii) a transition region; and (iii) an ordinary high-mobility slope (similar 2000 cm s⁻¹ Oe⁻¹). The initial low mobility at low drive field was increased about 2 times after x-ray irradiation. The ordinary high mobility at high drive field was slightly increased after irradiation. The difference in the improvement of mobility at the initial and ordinary slope after x-ray irradiation suggests that the damping mechanism of domain wall motion is not the same for these two regions.