Parametric amplification of spin waves using bulk acoustic waves

In this work, we investigate a novel technique of parametric amplification of spin waves using acoustic waves . Spin waves in a ferromagnetic film can be amplified by periodically changing the propagation parameters . Such parametric pumping using externally applied microwave magnetic fields, has been demonstrated in thin-film Yttrium Iron Garnet (YIG). Alternatively, as we demonstrate here, the effective anisotropy field may be modulated by acoustic waves via magneto-elastic coupling. The device used for our experiment consists of a thin film acoustic transducer fabricated on one side of a gadolinium gallium garnet (GGG) substrate with an epitaxial YIG film on the opposite side. Two microstrip antennae atop the YIG film are used respectively for the excitation and detection of spin waves in the YIG.