The change of the activation field in tgs crystal

Abstract

In the Miller and Weinreich model the apparent sidewise motion of a domain wall was realized by forming a nucleus, of opposite polarization one lattice constant thick, and then spreading it along the domain wall. Assuming the layer formation to be controlled by nucleation mechanism they got for the switching time of the crystal the following relations t_s t_oo exp/ ∞oC/E /, where ∞ is the activation field, E is the applied field. Assuming the nucleation is taking place at random sites on the domain wall and assuming the growth rate of a nucleus to be isotropic, for the time t₁needed to spread it on the layer we get: t_l ≅ u-2/3 exp/ ∞/3E /. For this process we observe the activation field to be diminished three times as compared to the situation, when nucleation rate is much smaller than the growth rate. In order to compute reliable values of the layer switching time from the crystal switching time, the measurements were carried out for an aged periodical domain structure. In this case, the domain shift is the same for all domain walls and the proportionality between t_s and t_l is readily established.