ELASTIC CONSTANTS AND LOSSES IN NICKEL 



977 



It is obvious from the measurements of Figs. 4 to 8 that the changes in 

 the elastic constants with magnetization are much smaller at the high fre- 

 quencies (10 mc) than they are at the lower frequencies of 10 to 50 kilo- 



1.2 



1.0 



0.8 



0.6 



0.4 



0.2 



•0.2 



-0.4 



1000 2000 3000 4000 5000 6000 



MAGNETIC FIELD STRENGTH,H, IN OERSTEDS 



Fig, 6 — Change in velocity in percent from demagnetized value as a function of the 

 magnetizing field for a shear wave in a (110) section when the particle velocity is along the 

 [OOlJ direction and the field along the [110] direction. 



cycles where changes of 15 to 30 per cent have been observed in polycrystal- 

 line material.' A rough comparison of the low-frequency values with the 10 

 megacycle values can be obtained if we convert the observed changes in the 

 c's to the equivalent change in £. This can be done if we use the method 



