1038 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1954 



wall, the voltage induced in the secondary winding during the pulse of 

 constant applied field is seen from the oscilloscope trace to distort 

 with time. Fig. 10 shows a series of traces observed at room temperature 

 on Sample 4 which show this distortion increasing from (a) to (d) as the 

 applied field is increased. At the highest fields the trace forms a peak 

 which is almost triangular in shape. 



We shall discuss the theoretical implications of these data in the next 

 two sections. 



(O 11,600 — 



£ 27,000 



62,000 — 



5/U. SEC 



Fig. 10 — A series of oscilloscope traces showing the deviation of the wall ve- 

 locity from a constant with time at the higher applied magnetic fields and there- 

 fore at the higher velocities. These pictures were taken at room temperature, hut 

 similar phenomena occur at all other temperatures in the range of applied fields 

 where the nonlinearity in velocity shown in Fig. 9 becomes apparent. The ve- 

 locities, as shown, increase from a to d. 



