Observation of domain expansion and contraction in thfe films by lorentz microscopy

Abstract

Lorentz electron microscopy techniques have been used to study in situ, at room temperature, the expansion and contraction of thermomagnetically written circular domains in Tb19Fe81and Tb32Fe68films. Very different behavior between these two films has been observed. Domains expand or contract More or less radially in Tb19Fe81, but with the development of jagged walls. In Tb32Fe68, dendrite-like stripe domains with jagged walls formed either outside or within the existing domains, leaving the perimeter of the initial circular domains unchanged. The different behavior between these two films can be understood based on the difference in the relative importance of the local demagnetizing field to the local total field. The implications of the observed nonuniform wall motion to the formation of domain irregularity during thermomagnetic recording are discussed. © 1988 IEEE