Magnetically Controlled Surface Acoustic Waves on Multiferroic BiFeO3

A surface acoustic wave (SAW) device, consisting of a pair of transducers on a piezoelectric substrate, works as a high-frequency band-pass filter. Usually the substrate is nonmagnetic, and the transmission strength and frequency cannot be controlled by an external field. This study reports a SAW device based instead on multiferroic BiFeO${}_{3}$; in this case, the amplitude and phase of the SAW signal $c\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}n$ be modulated by an external magnetic field, thanks to the coupled magnetoelastic response of the ferrite. This approach extends the functionality of such SAW devices, which are indispensable in communication technology (your mobile phone uses one, for example).