Spin wave resonance driven by surface acoustic wave via spin-rotation coupling in synthetic antiferromagnets

Synthetic Antiferromagnets (SAFs) have gained significant attention in the field of spintronics due to their high precession frequency and small stray field. Surface acoustic waves (SAWs) have been proved to generate spin current via spin-rotation coupling (SRC). In this work, we investigate the spin wave resonance driven by SAWs via SRC in a Py/Ru/Py/Cu compensated SAF with a nearly zero magnetostriction coefficient, which is composed of two ferromagnetic layers with equal thicknesses separated by a thin nonmagnetic Ru spacer layer. We use the Vector Network Analyzer to measure the transmission parameters S₂₁ and S₁₂ of the SAW devices. By manipulating the magnitude and direction of the external magnetic field H, both acoustic mode and optic mode can be clearly observed, causing a prominent acoustic attenuation that is significantly connected with the frequency of the SAW and the angle between H and the wave vector k of the SAW. Remarkably, the angle dependence of the acoustic attenuation intensity and the transmission nonreciprocity of our devices are substantially different from that caused by Magnetoelastic Coupling. We believe that the findings can promote the further development of magnetoacoustic devices.