Directly Excited Backward Volume Spin Waves in Permalloy Microstrips

A patterned magnetic microstrip will remain saturated along its length at remanence so the backward volume (BV) configuration is a natural geometry for spin wave devices, yet there are few experimental studies of spin waves in this geometry. In this paper, BV spin waves that were directly excited by a micrometer-sized antenna in a Permalloy microstrip were studied using microfocus Brillouin light scattering. The measured BV spin wave excitation efficiencies are approximately an order of magnitude smaller compared to the more commonly studied Damon-Eshbach configuration where the static magnetization is in-plane, perpendicular to the microstrip. Nevertheless, measureable signals were detected for a range of fields including zero magnetic field, which is important for applications.