Dynamic periodical distortions of stripe domains in garnet films (abstract)

Abstract

One of the problems arising in the development of VBL memory is to make stripe domains (SD) resistant to bending distortions. The paper considers a theoretical and experimental study of the mechanism of bending sinusoidal distortions of isolated SD caused by the sequence of bias fields (Hz) spatially homogeneous pulses compressing SD. The SD distortion dynamics was studied by the method of high speed photography with exposure of 10 ns. The SD critical width has been discovered. When reached, it first causes small distortions of the domain wall (DW). Further effects of the Hz pulses increases them, and after 10–12 field pulses the irreversible statically stable sinusoidal distortions of SD are finally formed. After that each subsequent Hz pulse just inverts the spatial structure of the distortions (i.e., transfers it from one bistable sin kx-type state to another: −sin kx). The performed theoretical analysis shows that the above effect is connected with the DB structure transformation observed when some critical SD width w* is reached. It has been experimentally discovered that the formed bending distortions of SD remain stable during the effect of the Hz pulse where SD width w≳w*, and tend to straighten when width w<w* is reached. The sequence of the above changes in the DW structure leads to the transition from one bistable state to another through an intermediate state with a small SD width. Experimentally found has been a close-to-linear dependence of spatial amplitude of distortions on the value of Hz. It has also been discovered that the distortions period and amplitude linearly increase together with the duration of Hz. The relation between the time of reaching w* and time of bending formation has been established.<UFMMM>