Magnetic tunnel junctions based on ferroelectric Hf0.5Zr0.5O2 tunnel barriers

TL;DR

This paper demonstrates a multiferroic tunnel junction using ultra-thin ferroelectric Hf0.5Zr0.5O2 barriers, achieving four stable resistance states through combined magnetic and electric control, promising for advanced microelectronics.

Contribution

It introduces a novel ferroelectric Hf0.5Zr0.5O2 barrier in MFTJs, enabling multiple resistance states with high reproducibility at nanoscale.

Findings

Four non-volatile resistance states achieved

Tunneling magnetoresistance can be tuned and reversed

High reproducibility of resistance states

Abstract

A ferroelectric tunnel barrier in between two ferromagnetic electrodes (multiferroic tunnel junction, MFTJ), is one of the most promising concepts for future microelectronic devices. In parallel, Hafnia based ferroelectrics are showing great potential for device miniaturization down to the nanoscale. Here we utilize ferroelectric Hf0.5Zr0.5O2 (HZO) with thickness of only 2 nm, epitaxially grown on La0.7Sr0.3MnO3 (LSMO) ferromagnetic electrodes, as a large band-gap insulating barrier integrated in MFTJs with cobalt top electrodes. As previously reported for other MFTJs with similar electrodes, the tunneling magnetoresistance (TMR) can be tuned and its sign can even be reversed by the bias voltage across the junction. We demonstrate four non-volatile resistance states generated by magnetic and electric field switching with high reproducibility in this system.