Behavior of bloch lines in epitaxial garnet films subjected to an in-plane field

Abstract

A recent experiment shows that when the stripe domain in garnet bubble films is subjected to an in-plane magnetic field H at zero static bias field, there exists a critical value, H', of H: When H < H', the number of same sign VBLs contained in the domain wall keeps unchanged. When H > H', however, those VBLs disappear. In our present work, a theoretical research on this phenomenon is carried out in the framework of micromagnetics, by examining the positive definiteness of an appropriate 1-D homogeneous quadratic functional. Results of numerical analysis by means of the finite element method indicate that there exists a critical in-plane field H' indeed and H'/H k is uniquely determined by the quality factor Q of the samples. Here H k is the uniaxial anisotropy field. A measurement of the dependence of H'/H k on Q for eight samples is made. It turns out that the theory agrees fairly well with the experiment.