Measurement of Bloch line coercivity in uniaxial garnet films

The coercive field of vertical Bloch lines in several uniaxial garnet film samples has been measured by two different methods. With the first method, individual isolated Bloch lines in stripe-domain walls and their response to external magnetic fields are observed directly using a one-sided dark-field illumination technique. The second method detects Block line motion in bubble-domain walls photometrically. By measuring over an array of bubble domains, an average of the scatter of coercivity data is obtained. Experimental results are presented.<>