Relaxation time of parametrically excited magnetostatic modes in YIG

Parallel pumping experiments were conducted on a single-crystal yttrium iron garnet sphere. Microwave radiation from magnetostatic modes, which were parametrically excited through parallel pumped spin-waves, was studied experimentally at several temperatures. As excitation microwave power is turned off, it will be thought that microwave radiation decreases exponentially. Relaxation time of a magnetostatic mode, which is excited beyond thermal equilibrium level, is estimated by this method.