Electric steering of spin excitation in nanostructured synthetic antiferromagnet

Abstract

Two or more ferromagnetic layers separated by metallic nanoscale spacers may couple antiferromagnetically forming a synthetic antiferromagnet (SAF) with versatile functionalities that are derived from their ferro- and antiferromagnetic nature. Here, we present a nanostructure consisting of a SAF deposited on a conductive substrate with strong spin–orbit coupling. As demonstrated analytically and fully numerically, the system exhibits exceptional points at which a charge current flowing in the substrate results in extraordinary characteristics of magnetic excitation and signal propagation in the SAF. We predict local electric steering, amplification, and damping of magnonic excitations by tuning the voltage on the substrate. Electrical amplification and local control of spin-pumping currents are also demonstrated. The results point to an alternative way for electrical spatiotemporal control of the nanoscale SAF with promising applications in spintronics and spin-based logic computing.