Field-Free Magnetization Switching by an Acoustic Wave

Surface acoustic waves (SAWs) propagating on magnetostrictive ferromagnets can induce magnetization reversal: their weak damping and mature technology make them ideal for remote wave control of magnetic bits. Experimental demonstrations of this spectacular coupling have so far required the simultaneous application of a static magnetic field. We show here SAW-driven all-acoustic switching (AAS) over millimetric distances. It relies on the triggering of magnetization precession of a uniaxial in-plane magnetized film by acoustic ferromagnetic resonance at zero field. Moreover, the absence of a biasing field enables toggling between the two equilibrium magnetic states for over 20 consecutive acoustic pulses. This proof-of-concept opens up an alternative path to magnetic-bit manipulation.