A Directional Metamaterial: Controlling Information Flow using In-plane Magnetic Fields

A wide range of spin-based systems have recently emerged as candidates for novel neuromorphic computing devices. One such system is artificial spin ice (ASI), a class of magnetic metamaterials consisting of interacting bistable nanomagnets. Recently, we have shown that we can control the magnetic states of ASIs using astroid clocking, a method which uses global magnetic field pulses to gradually grow and shrink domains in an ASI[1]. Although astroid clocking offers control necessary for computation, domains grow equally in opposite directions, making it difficult to propagate signals through the ASI. Controlling directional information flow, which is a requirement for successful computation[2], thus remains a challenge. We present directional ASIs, a novel class of ASI geometries designed to support directional flow of information. By subjecting an ASI to a series of in-plane magnetic fields, simulations show that we can produce a variety of magnetic states which reliably grow and move in a single direction. In this work, we seek to experimentally characterize the so-called directionality of our system by investigating the dynamics of the magnetic states of a directional ASI as it is subjected to global in-plane field protocols.