Acoustic driven magnonics (Conference Presentation)

Abstract

Magnonics aims to utilize magnons (quanta of spin-waves) to process and transfer digital and analog information, promising high throughput, low power computing for the post-CMOS era. Any such future magnonic circuits will require spin wave signal sources and amplifiers. We propose that acoustic pumping of spin waves provides a mechanism to implement these functions in efficient and highly localized devices. In support of this, we have developed a general theoretical model of linear and parametric magneto-acoustic interactions, covering all possible polarizations of acoustic waves and spin wave modes. The model combines the predictive power of analytical techniques with numerical micromagnetic simulations and is thus well-suited for the design of complex physical devices. Based on this, we determine the configurations most amenable to spin wave generation and amplification. As an experimental prototype we demonstrate an acoustically-pumped amplifier for spin-waves. Our device consists of an yttrium-iron-garnet (YIG) film grown on a gallium gadolinium garnet (GGG) substrate, with a bulk acoustic waves (BAW) transducer fabricated on the top of the GGG substrate. We show experimentally that the amplitude of the propagating spin-waves increases with the application of the BAW. Moreover, this scheme can be used as a signal correlator, where the modulated spin-waves and acoustic waves serve as signal inputs and the resulting modulation of the amplified spin wave serves as the output.