Low Power Nonlinear Effects in the Ferromagnetic Resonance of Zn2Y and MnZnY Hexagonal Ferrites

摘要

The room temperture ferromagnetic resonance (FMR) absorption at 8.9 -11.2 GHz in two planar hexagonal ferrites, Zn2Y and MnZnY, has been found to exhibit strong nonliner behavior at low power levels corresponding to microwave field amplitudes, 20-50 mOe, the asymmetric resonance curves show pronounced foldover effects. With increasing static field, the absorption increases on the order of 109 mOe. For somewhat larger amplitudes, gradually to steep cutoff at a field several hundred Oe above the position of the low power FMR. With decreasing field, a sharp spike occurs coincident with the high field tail of the low power FMR line, followed by a gradual decrease which tracks the upsweep absorption. The detailed shapes of these curves depend strongly on sweep rate. Steady-state absorption curves at the highest powers employed, with 350 mW incident power and a microwave field amplitude of 58 mOe, result only for very slow sweep rates fo 20 Oe/min or less. Keywords: Zinc compounds; Manganese compounds; Ba2Zn2Fe12022; Reprints.