Dipolar spin wave properties excited by a perpendicular magnetic anisotropy magnetic waveguide

Spin waves, a collective magnetic precession phenomenon, offer promising potential for advanced microwave signal processing. This study investigates spin wave propagation in La: YIG thin films, where the waveguide structure itself is designed with perpendicular magnetic anisotropy (PMA) to optimize microwave signal transmission. A 100 nm thick La:YIG film was grown on a GGG substrate using liquid-phase epitaxy (LPE), and coplanar waveguide (CPW) antennas were fabricated using photolithography and magnetron sputtering. Spin wave transmission was characterized via a vector network analyzer (VNA), measuring two modes: Magnetostatic Surface Spin Waves (MSSW) and Backward Volume Magnetostatic Waves (BVMSW). The results reveal that the PMA-based waveguide significantly enhances spin wave propagation, with MSSW mode achieving superior microwave bandpass filtering performance (4.9 dB insertion loss) compared to BVMSW mode (16.5 dB). Moreover, the calculated group velocity in the MSSW mode was 0.864 km/s, 72.8% higher than that of pure YIG, demonstrating the crucial role of PMA in enhancing device performance for microwave signal processing.