Magnetic Steering of Magnetostatic Waves in Epitaxial YIG Films

Abstract

High quality epitaxial YIG films grown on gadolinium gallium garnet have certain geometrical advantages over flux‐grown material for refined investigation of basic magnetic wave propagation phenomena. Better uniformity of internal field under magnetic bias and convenience for placement of spatially periodic current‐carrying couplers on the free YIG surface, ensures enhanced field uniformity by confining the region of propagation. Surface magnetostatic waves are dispersive and exhibit wave vector anisotropy so that, in general, the phase and group velocity vectors are noncollinear, with the beam steering angle variable by the magnetic bias field. Scanning magnetic probe experiments were conducted at 3 GHz on 10‐μm thick films wherein beam steering angles were observed up to ∼50° for a wave number approximating 830 cm⁻¹, for a 10° rotation of the bias field from the collinear situation. Use of the theoretical model applicable to thin film media, which neglects exchange effects, led to good agreement with the experimental results within measurement error.