Interactions of Parametric Magnons in Ferromagnets

Abstract
Conditions for the appearance of the three, four, and five magnon fusions have been derived by Gottlieb and Suhl by making use of the dispersion relation of the spin wave, restricted to the Zeeman and exchange terms. In this paper we have determined these conditions of existence from the correct relations of dispersion containing the dipolar term neglected in the previous calculations. Experimental studies of the transient growth of parallel‐pumped spin waves are in good agreement with these theoretical results, thus verifying that the parametric magnons are propagating perpendiculary to the dc magnetic field as predicted by the theory of Sparks and Kittel.