Аннотации:
This paper reports a detailed measurement of Mz, the component parallel to the effective field direction, when ferromagnets are excited by microwave fields at high power levels. It is found that Mz drops dramatically at the saturation of the main resonance. Simultaneous measurements of Mz and absorption power show that this drop corresponds to a diminution of the spin-lattice relaxation rate. These changes are interpreted as reflecting the properties of longitudinal spin waves excited above Suhl's instability. © 2005 The American Physical Society.