A magnetic domain wall Mackey–Glass oscillator

Abstract

We propose a time-delay oscillator using Mackey–Glass nonlinearity based on a pinned magnetic domain wall in a thin film nanostrip. Through spin transfer torques, electric currents applied along the strip cause the domain wall to deform and displace away from a geometrical pinning site, which can be converted into a nonlinear transfer function through a suitable choice of a readout. This readout serves as a delay signal, which is subsequently fed back into the applied current with amplification. With micromagnetics simulations, we study the role of the readout position, time delay, and feedback gain on the dynamics of this domain wall. In particular, we highlight regimes in which self-sustained oscillations and complex transients are possible.

Magnetic domain walls: types, processes and applications

“…This is particularly exciting for RC as the nonlinear transformations using 'edge-of-chaos' dynamics should offer rich and tunable performance. Williame and Kim [247] (Type:Sim) demonstrated Mackey-Glass oscillator behaviour in simulations of STT-driven DW motion in a nanowire with an elliptical protrusion, although they commented that, in practice, current-driven heating of the device and fabrication uncertainties might affect device performance.…”