Temperature dependence of the exchange interaction constant in iron garnet films

The spin-wave resonance method is used to investigate the temperature dependence of the exchange interaction constant A in iron garnet films. The experimental results are compared with theoretical results based on the theory of second-order phase transitions. It is shown that the temperature dependence A(T) for films of pure yttrium iron garnet is different from A(T) for films exhibiting a point of compensation of the magnetic moment. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 7, 528–532 (10 April 1996)