Parametric excitation of surface magnetostatic modes in an axially magnetized elliptic cylinder under longitudinal pumping

摘要

A rigorous analytical theory of parametric excitation under the longitudinalpumping has been developed for the surface magnetostatic modes of a longelliptic ferrite cylinder magnetized along its axis with regard for theboundary conditions at the surface of the cylinder.It is shown that a pair offrequency-degenerated counter-propagating surface modes at half the pumpingfrequency can be parametrically excited, and the expressions for thecorresponding parametric excitation threshold have been derived. The thresholddemonstrates a strong dependence on the mode number and elliptic cylinder'saspect ratio and tends from above for the large aspect ratio to the valuededuced on the basis of the plane-wave analysis.The simple analytical relationbetween the ratio of axes of the high-frequency magnetization polarizationellipse of excited surface magnetostatic oscillations and the parametricexcitation threshold is obtained, discussed, and graphically illustrated.