Voltage-Controlled Low-Energy Switching of Nanomagnets through Ruderman-Kittel-Kasuya-Yosida Interactions for Magnetoelectric Device Applications

In this letter, we consider through simulation Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between nanomagnets sitting on a conductive surface, and voltage-controlled gating thereof for low-energy switching of nanomagnets for possible memory and nonvolatile logic applications. For specificity, we consider nanomagnets with perpendicular anisotropy on a three-dimensional topological insulator. We model the possibility and dynamics of RKKY-based switching of one nanomagnet by coupling to one or more nanomagnets of set orientation. Applications for both memory and nonvolatile logic are considered, with follower, inverter and majority gate functionality shown. Sub-attojoule switching energies, far below conventional spin transfer torque (STT)-based memories and even below CMOS logic appear possible. Switching times on the order of a few nanoseconds, comparable to times for STT switching, are estimated for ferromagnetic nanomagnets.