The temperature dependence of the coercivity Hc, magnetization, anisotropy, and domain wall energy was measured for SmGaYIG, SmCaGeYIG, and SmLuCaGeYIG epitaxial bubble garnet films from 100 K up to the Néel temperature TN≳400 K. Data were analyzed together with results published on similar samples on the basis of the theory of domain wall pinning by a random array of uniform defects and a good fit was observed in the form of H1/2c=H1/20 -CT2 /3, where H0 and C are constants. The maximum average interaction force between defects and walls is 2.9×10 -7 dyne, corresponding to the minimum interaction range equal to the wall width. The density of defects is in the range between 10 14 and 1016 cm- 3. The size and number of defects derived from the temperature dependence of Hc is in agreement with the microstructure of epitaxial garnets revealed by transmission electron microscopy.
ASJC Scopus subject areas
- Physics and Astronomy(all)