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BELL SYSTEM TECHNICAL JOURNAL 



baking treatment. A similar type of constricted loop can be obtained 

 in a magnetic sample which is composed of thin parallel sheets of a soft 

 and of a hard magnetic material magnetized longitudinally. 



It may be that the two constituents result from a process similar to 

 that described for the iron-nickel alloys in the region of 75 per cent 



16000 



14000 



1 0000 



$ 8000 



z 



4000 



30 40 



H IN OERSTEDS 



Fig. 11 — Magnetization curves for a perminvar containing 45 per cent nickel, 25 

 per cent cobalt and 30 per cent iron after several heat treatments — Elnien ''. 



nickel. In line with this, the baking treatment may form a super- 

 structure 2* which is magnetically hard, but to a greater degree, than 

 the one in the binary iron-nickel alloys. It is probable that the similar 

 effects of heat treatments in the binary and ternary alloys are due to 

 similar structural transformations. 



