Thermally Activated Domain Wall Movement

Magnetization reversal by slow domain wall motion under constant applied field has been observed by the Faraday effect in permalloy films. A quantitative study (Craik and Wood 1965) of the dependence of wall velocity on temperature and field has been made in the temperature range −47 to +22°C. The linear relationship between the field H and the logarithm of velocity is consistent with previous work, but in addition the variation of the slope of this line with temperature is noted. The analysis of the results is based on Stacey's theory for uniform potential barriers, and an activation volume deduced which is approximately equal to the cube of the film thickness. An estimate is also made of the frequency factor incorporated in the theory, which is consistent with theoretical values. The validity of these calculations is discussed.