402 



THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



is rising, with increase of frequency, from its negative-infinite value at 

 VQ to its asymptotic value of zero at infinite frequency, the permeability 

 is rishig from negative infinity to an asymptotic value which is equal to 

 + 1. Somewhere along this range of frequencies it must pass through 

 zero, at a frequency to be denoted by vi . For a stratum parallel to both 

 the big applied field and the oscillating field, it is easily shown that vi 

 is equal to {ge/^Trmc)B. This offers a way of determining B and conse- 

 quently M. 



< 



1 2 3 4 5 6 7 8 9 10 11 12 1 3 14 15 16 17 



INTERNAL STATIC MAGNETIC FIELD, Hz, 'N KILO-OERSTEDS 



Fig. 4. — Ferromagnetic resonance in Heusler alloy (Cu-Mn-Al). "Apparent" 

 permeability is plotted against H at constant frequency: the resonance-maximum 

 (at the position corresponding to g = 2.02) is vividly shown, as is the minimum 

 mentioned in the text. The solid curve is a theoretical curve based on a specific 

 assumption about damping. (W. A. Yager and F. R. Merritt). 



