Orientation dependence of dipole gaps in the magnetostatic wave spectrum of Bi-substituted iron garnets

Abstract

The orientation dependence of the dipole-exchange gaps in the magnetostatic forward volume wave spectrum of Bi0.8Lu2.2Fe5O12 thin films grown from a Bi-oxide flux has been studied. The spectrum is relatively insensitive to tilting the bias field toward the direction of propagation, but significant improvements are observed when the field is tilted toward a direction perpendicular to the propagation direction. Improvements include smoothing of the dipole-exchange gaps and a reduction of the insertion loss. These improvements are nonreciprocal; either reversing the direction of propagation or tilting the bias field in the opposite direction degrades the forward volume wave spectrum.