PERMALLOY, A NEW MAGNETIC MATERIAL 



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strengths by ballistic methods. Figs. 3, 4, and 5 show B-H curves for 

 such a sample of permalloy and for a sample of annealed armco iron. 

 From Fig. 5 is apparent the enormous susceptibility of the former 

 material in the weak fields so important in communication engineer- 

 ing. Fig. 6 shows for the same two materials hysteresis loops carried 

 to a maximum induction of 5000 maxwells. The area of the permalloy 

 loop is only one sixteenth that of the loop for soft iron. Fig. 7 shows 



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the m-B curves for these materials. The maximum permeability here 

 shown, n = 87000, which is not exceptionally high for permalloy 

 largely exceeds the highest values obtainable in silicon steel 5 and of 

 course occurs at a much lower flux density. 



5 T. D. Yensen, U. S. Patent 1,358,810. 



