Electrically reversible cracks in an intermetallic film controlled by an electric field

Z.q Liu ,R Ramesh,J.m Wang ,Ming Lin ,Han Yan ,Anthony T Wong ,Shang‐Lin Hsu ,Long You ,Zexin Feng ,Thomas Z Ward ,Z.k Liu ,Bernd Gludovatz ,Jia Mian Hu ,Chengbao Jiang ,Cassie Marker ,R.o Ritchie ,Shun‐Li Shang ,Yanzhou Ji ,Lei Chen ,Megan J Cordill ,Michael D Biegalski ,J.h Liu ,Hans M Christen

doi:10.1038/s41467-017-02454-8

Abstract

Cracks in solid-state materials are typically irreversible. Here we report electrically reversible opening and closing of nanoscale cracks in an intermetallic thin film grown on a ferroelectric substrate driven by a small electric field (~0.83 kV/cm). Accordingly, a nonvolatile colossal electroresistance on–off ratio of more than 108 is measured across the cracks in the intermetallic film at room temperature. Cracks are easily formed with low-frequency voltage cycling and remain stable when the device is operated at high frequency, which offers intriguing potential for next-generation high-frequency memory applications. Moreover, endurance testing demonstrates that the opening and closing of such cracks can reach over 107 cycles under 10-μs pulses, without catastrophic failure of the film.

Highlights

Cracks in solid-state materials are typically irreversible
We demonstrate a new type of heterostructures consisting of intermetallic alloys and ferroelectric oxides for room-temperature memory applications; interestingly, we can utilize precisely the otherwise problematic existence of cracks to create a functional device
Instead of utilizing electronic phase transitions of intermetallic alloys and the piezoelectric effect of ferroelectric oxides, here we propose to employ the mechanical properties of intermetallic alloys and the opening/closing of cracks induced by cyclic electric fields in ferroelectric oxides

Summary

Introduction

Cracks in solid-state materials are typically irreversible. Here we report electrically reversible opening and closing of nanoscale cracks in an intermetallic thin film grown on a ferroelectric substrate driven by a small electric field (~0.83 kV/cm). Recent efforts on the integration of magnetic intermetallic alloy thin films with functional ferroelectric oxides have created exciting opportunities for manipulating magnetism and resistivity of intermetallics via small electric fields, which offers great promise for low-energy-consuming memory device applications[1,2,3,4,5]. Such heterostructures, such as FeRh/BaTiO3 and FeRh/0.72PbMg1/3Nb2/3O3–0.28PbTiO3 (PMN-PT), rely on the strong interfacial-strain-mediated magnetoelectric coupling between the piezoelectric effect in the ferroelectric layer and the phase instability around the phase transition of the FeRh layer to generate giant magnetization and resistivity modulation[1,2,4]. Intermetallic alloys are precisely the right materials to be considered for such a structure

Methods

Results

Conclusion