EuTe is a second kind f. c. c. antiferromagnet. The line width of the antiferromagnetic resonance of the single crystal has been measured at frequencies of 9.20, 22.12, and 33.99 GHz in the temperature range between 1.25 and 4.20 K. The measurements have been performed on the spin-flop mode with the resonance field applied in the easy plane (111). The results show that the temperature dependence of the line width strongly depends on the used frequency. The line width at 9.20 GHz increases with temperature as exp (-5/T), the one at 22.12 GHz increases linearly with T, and at 33.99 GHz it increases very slowly with T. The essential behavior of the temperature and frequency dependences is theoretically explained in terms of the three-magnon process derived from the exchange interaction
