The behaviour of damping motion of domain walls in (BiTm)3(FeGa)5O12 thin film

The displacement of domain walls in the film of (BiTm)(3)(FeGa)(5)O-12 has been studied experimentally under the conditions of increasing applied magnetic field with change rates of R = dH/dt = 0, 67, 358 and 401(A/m(-1))s(-1). The relationship between the displacement Delta X and the magnetic field H was established using the experimental data obtained by the photographic technique. On the other hand, the experimental results are interpreted based on the fundamental equation that describes the motion of domain wall under a magnetic force. We note that the damping coefficient alpha for our sample was shown to be very small (alpha approximate to 10(-6)). It increases with increasing the change rate of the magnetic field R. It is also shown that the equivalent resistant field, H-r, for our sample is relatively large. Furthermore, we note that for the case of zero change rate, i.e. R = 0, the applied field that corresponds to the Faraday's rotation angle for the saturation state is approximately determined by the value of the magnetic field at which the turning point in the Delta X vs H curve occurs. Copyright (C) 1997 Elsevier Science Ltd