Magneto-ionic enhancement and control of perpendicular magnetic anisotropy
Alexander E. Kossak, Daniel Wolf, Geoffrey S. D. Beach
Abstract
Magneto-ionic control of magnetic anisotropy is an emerging voltage-controlled approach that aims to offer much lower power consumption than current-controlled manipulation of magnetization. Moreover, magneto-ionic systems are ideal candidates for non von Neumann computing architectures, such as neuromorphic and stochastic computing due to their non-volatile and analog nature. One of the key metrics to quantify the efficiency of voltage-controlled magnetic anisotropy (VCMA) is the magneto-electric voltage coefficient (ΔHc/|ΔV|). Here, we show greater than one order of magnitude improvement in this efficiency compared to existing solid-state systems using a Co/Pd multilayer heterostructure. By performing a systematic study of the Co thickness, the Pd thickness, and the number of repeat units of engineered Co/Pd multilayers, we identify a narrow bandwidth of the Co thickness from 2–2.5 Å, Pd thickness from 1.4–1.7 nm, and repeat units from 7–9, to maximize the VCMA. Compared to rivaled liquid electrolyte systems, this platform has the advantage of faster speeds and easier integration for on-chip logic and memory devices.