MAGNETIC MATERIALS IN RELATION TO STRUCTURE 



39 



300° C. the magnetization is readily accomplished. In this procedure 

 the magnet is cooled in the magnetizing field. If the magnet has once 

 been magnetized at the high temperature, succeeding magnetizations 

 can be carried out at room temperature. 



Fig. 20 — The same alloy as shown in Fig. 19 after a subsequent aging treatment of 

 5 hours at 725° C. Mag. 125 X. 



The mxagnetic characteristics of the material are illustrated in Fig. 21, 

 in which a hysteresis loop for a metallic oxide magnet is compared with 

 one for carbon steel. The coercive force of the new material is ap- 

 proximately 600 oersteds and the residual intensity of magnetization, 

 320 units, corresponding to a residual induction of approximately 

 4000 gauss. 



The high coercive force of the oxide magnet makes possible the more 

 exact location of poles and permits the utilization of the material in 



