Spin Logic Devices via Electric Field Controlled Magnetization Reversal by Spin-Orbit Torque

Abstract

We describe a spin logic device with controllable magnetization switching of perpendicularly magnetized ferromagnet / heavy metal structures on a ferroelectric (1-x)[Pb(Mg1/3Nb2/3)O3]-x[PbTiO3] (PMN-PT) substrate using current-induced spin-orbit torque. The devices were operated without an external magnetic field and controlled by voltages as low as 10 V applied across the PMN-PT substrate, which is much lower compared to previous reports (500 V). The deterministic switching with smaller voltage was realized from the virgin state of the PMN-PT. Ferroelectric simulation shows the unsaturated minor loop exhibits obvious asymmetries in the polarizations. Larger polarization can be induced from the initial ferroelectric state, while it is difficult for opposite polarization. The XNOR, AND, NAND and NOT logic functions were demonstrated by the deterministic magnetization switching from the interaction between the spin-orbit torque and electric field at the PMN-PT/Pt interface. The nonvolatile spin logic scheme in this work is simple, scalable, programmable, which are favorable in the logic-in-memory design with low energy consumption.

Tailoring Multilevel‐Stable Remanence States in Exchange‐Biased System through Spin‐Orbit Torque

“…[ 31 ] Thus, not only the magnetization but also the exchange‐bias are reversed by SOT. Due to the deterministic magnetization switching by SOT, [ 11–13,26–30 ] only the up (down) magnetized domain could be switched to opposite direction under a positive (negative) current pulse with an assistance field of + H x , as schematically shown in Figure 1e,f. Thereby, concurrent switching of FM magnetization and AFM interfacial spins by SOT can be realized.…”

“…The SOT effect has been demonstrated as an efficient way to switch the magnetization of FM or AFM, and was widely investigated owing to its potential applications in magnetic random access memory (MRAM) and other spintronic devices. [ 11–13,26–30 ] In particular, in HM/FM/AFM trilayers, Lin et al recently reported that the hysteresis loops between positively and negatively single‐biased loops could be manipulated by SOT through switching the FM spins and AFM interfacial spins completely and simultaneously with magneto–optical Kerr techniques. [ 31 ] It provides an effective approach to manipulate the FM magnetization and AFM interfacial spins in HM/FM/AFM trilayers by SOT.…”

Current‐Induced Spin–Orbit Torques for Spintronic Applications

“…For instance, it can drive domain walls or skyrmions effectively, [36,[167][168][169][170] facilitating chiral-spin-texturebased memory or logic devices. [16,83,84,90,[171][172][173][174][175] Moreover, it enables the demonstration of memristive behavior in a spintronic device, [106,164,165,[176][177][178] which can perform synaptic functions in artificial neural networks.…”

Deterministic Magnetization Switching Using Lateral Spin–Orbit Torque

“…[ 10–13 ] The resulting SOT‐induced effective magnetic field is in‐plane, hence an additional orthogonal in‐plane magnetic field is required to realize deterministic switching of a PMA‐FM. To date, several approaches for field‐free SOT‐induced PMA‐FM switching have been proposed and demonstrated, such as switching using a polarized ferroelectric substrate induced in‐plane spin current gradient, [ 14–16 ] a wedge oxide capping layer, [ 17 ] a tilted PMA layer, [ 18 ] a stack with coherent in‐plane exchange field, [ 19–23 ] an interplay of SOT and STT, [ 24,25 ] an in‐plane‐FM/normal metal/PMA‐FM trilayer, [ 26 ] and a particular low symmetric WTe 2 semimetal. [ 27 ] However, the concomitant complexities of these approaches highlight the inherent limitation of the conventional SOT scheme utilizing external out‐of‐plane spin current injection in a perpendicular asymmetric structure.…”