Magnetoelectric memory using orthogonal magnetization states and magnetoelastic switching

Abstract

We present here a concept of a memory cell called MELRAM based on a magnetic element with giant magnetostriction, embedded in a piezoelectric matrix. Two equilibrium orientations of magnetization are defined by combining uniaxial anisotropy together with a magnetic polarization in the hard axis direction. Using the piezoelectric matrix, an anisotropic stress is created onto the magnetic element when applying a voltage across electrodes. Thanks to the inverse magnetostrictive effect, the effective anisotropy of the magnetic element is controlled by the applied voltage and used to switch magnetization from one state to the other. Micromagnetic simulations show the effect of applied stress on magnetization and theoretical feasibility of the device. Retrieval of information can be nondestructively made by giant magnetoresistance reading. Details of the principle, simulations, and performance perspectives are discussed.