Strain-induced resistance change in V2O3 films on piezoelectric ceramic disks

Joe Sakai,Beatrice Negulescu,Maxime Bavencoffe,Akinori Tateyama,Hiroshi Funakubo,Jérôme Wolfman,Patrice Limelette

doi:10.1063/1.5083941

Abstract

We prepared a stacked structure consisting of a quasi-free-standing functional oxide thin film and a ceramic piezoelectric disk and observed the effect of the piezoelectric disk deformation on the resistance of the thin film. Epitaxial V2O3 films were grown by a pulsed laser deposition method on muscovite mica substrates, peeled off using Scotch tapes, and transferred onto piezoelectric elements. In this V2O3/insulator/top electrode/piezoelectronic disk/bottom electrode structure, the resistance of the V2O3 film displayed a variation of 60% by sweeping the piezoelectronic disk bias. With support from x-ray diffraction measurements under an electric field, a huge gauge factor of 3 × 103 in the V2O3 film was inferred. The sizeable resistance change in the V2O3 layer is ascribed to the piezo-actuated evolution of c/a ratios, which drives the material towards an insulating phase. A memory effect on the resistance, related to the hysteretic displacement of the piezoelectric material, is also presented.

Highlights

Among the various materials whose physical properties are strain dependent, vanadium sesquioxide (V2O3) has been of great interest for half a century because of its rich temperaturepressure phase diagram
It is known that the c/a ratio of V2O3 jumps at the transition, i.e., c/a is high (>2.815) in the paramagnetic metal (PM) phase, while it is low (
X-ray diffraction (XRD) analysis of the obtained V2O3 films on the mica substrates revealed that the films were out-of-plane oriented along its c-axis [Fig. 2(a)] and in-plane oriented in sixfold symmetry [Fig. 2(b)], suggesting the epitaxial growth of the films

Summary

INTRODUCTION

Among the various materials whose physical properties are strain dependent, vanadium sesquioxide (V2O3) has been of great interest for half a century because of its rich temperaturepressure phase diagram. We prepared a series of V2O3 films on sapphire substrates with various deposition conditions, resulting in a wide range of c/a ratios Their physical properties, such as the PM–AFI phase transition temperature and resistivity ratio between high and low temperatures, were revealed to be clearly dependent on the c/a ratio at RT.. We have used a conductive atomic force microscopy (C-AFM) system to apply a local pressure of subgigapascal to a c axis-oriented V2O3 film and achieved obvious metal–insulator transition.. The structure consists of a quasi-free-standing V2O3 film fixed on an M–I–M-structured piezoelectronic element, with neither a rigid frame nor an AFM tip Such a design was inspired by a number of previous studies on strain-induced modification of magnetic properties of thin films placed on piezoelectric bases.. We observed a sizeable variation of RV2O3 that can only be explained by the resistivity change due to the piezo-induced modification of its c/a

Films deposition process and crystallographic characterization

Electrical and mechanical properties measurement

RESULTS AND DISCUSSION

CONCLUSIONS