Design of a Voltage‐Controlled Magnetic Random Access Memory Based on Anisotropic Magnetoresistance in a Single Magnetic Layer

Abstract

A simple and fully gate-voltage-controlled magnetic random access memory is designed based on anisotropic magnetoresistance. This multiferroic memory device consists of just a single magnetic film grown on a ferroelectric layer with bistable in-plane anisotropic ferroelastic or piezo strains induced by out-of-plane voltages. It can simultaneously achieve ultrahigh storage density, ultralow energy consumption, and GHz high-speed operation at room temperature.

Film size-dependent voltage-modulated magnetism in multiferroic heterostructures

“…Nevertheless, the magnetization switching would somewhat be restricted in the single-domain 32 nm case as well (i.e. a rotation of about 65 • at E = 0) owing to enhanced lateral demagnetization [60]. Accordingly, there would be an optimized lateral size where the magnetization rotation can reach a peak, which is deduced to be around 64 nm based on the simulation results in figure 7.…”

“…the length and width, assumed to be equal herein) of the magnetic film would also exert significant influence on the domain states as a result of the competing exchange and magnetostatic energy [79,80], for example, the film would display a uniform single-domain structure at small sizes owing to the dominative exchange anisotropy, whereas it would be in a multi-domain state at large sizes in order to reduce the magnetostatic energy. These domain structures would lead to different voltage-induced magnetizationswitching characteristics accordingly [57,58], which is critical to the potential device application [59,60]. Here, we use a phase-field model [81][82][83] to investigate such lateral size-dependent voltage manipulation of magnetization.…”

“…Both of the E-induced magnetization-switching processes can be completed with less than 10 ns, demonstrating an intrinsically fast (GHz) operation speed. Based on such E-induced bistable in-plane 90 • magnetization switching in a multiferroic magnetic/FE-layered heterostructure, new voltage-actuated MRAM devices have been proposed [59,60], which could simultaneously achieve ultralow write energy, ultrahigh storage density and room-temperature GHz operation.…”

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components

“…For example, phase-field method has been applied to modeling the converse ME switching of magnetization in nanoscale layered heterostructures. 205,206 It allows one to obtain the electric field induced changes in both the macroscopic magnetization and magnetic domain structures. Phase-field simulations have the potential to guide the design of devices.…”

“…Phase-field simulations have the potential to guide the design of devices. A Strain-Mediated Magneto resistive Random Access Memory (SM-MRAM) 206 was designed through phase-field simulations, which is predicted to possess ultrahigh storage capacity, ultralow power dissipation, and room-temperature high-speed operation simultaneously, thus, offering a potentially significant improvement over existing MRAM technologies or existing device concepts. However, there are several challenges that need to be overcome in order to make phase-field simulation a routine tool to fundamentally understand the basic mechanisms underlying the multifunctionality of heterostructures and to assist or guide the design of devices.…”