# Demonstration of a strain-mediated magnetoelectric write and read unit in a Co60Fe20B20/ Pb(Mg1/3Nb2/3)0.7Ti0.3O3 heterostructure

## TL;DR

This paper demonstrates a room-temperature, strain-mediated magnetoelectric write and read system in a heterostructure, enabling magnetic state control and detection without magnetic fields, with results aligning with a theoretical model.

## Contribution

It introduces a novel magnetoelectric heterostructure that enables simultaneous write and read operations via strain effects without symmetry breaking magnetic fields.

## Key findings

- Magnetic easy axis can be rotated by applying voltage.
- Magnetization changes induce measurable piezoelectric potentials.
- Experimental results agree with a theoretical equivalent circuit model.

## Abstract

Taking advantage of the Magnetoelectric (ME) and its inverse effect, this article demonstrates strain-mediated magnetoelectric write and read operations simultaneously in Co60Fe20B20/ Pb(Mg1/3Nb2/3)0.7Ti0.3O3 heterostructures without using any symmetry breaking magnetic field at room temperature. By applying an external DC-voltage across a (011)-cut PMN-PT substrate, the ferroelectric polarization is re-oriented, which results in an anisotropic in-plane strain that transfers to the CoFeB thin film and changes its magnetic anisotropy Hk. The change in Hk in-turn results in a 90o rotation of the magnetic easy axis for sufficiently high voltages. Simultaneously, the inverse effect is employed to read changes of the magnetic properties. Because the Piezoelectric (PE)/FerroMagnetic (FM) system is fully coupled, the change of magnetization in FM induces an elastic stress in the PE layer, which generates a piezoelectric potential in the system that can be used to readout the magnetic state of the FM layer. Our experimental results are in excellent qualitative agreement with a recently proposed, experimentally benchmarked equivalent circuit model that considers how magnetic properties are electrically controlled in such ME/PE heterostructure and how a back-voltage is generated due to changing magnetic properties in a self-consistent model.

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Source: https://tomesphere.com/paper/1901.01368