Signature of persistent metallic domains in FORC measurements of the VO$_2$ metal-insulator transition

TL;DR

This study uses first order reversal curve measurements to identify metallic domains in VO$_2$ during its metal-insulator transition, revealing inter-domain interactions as key to hysteresis behavior.

Contribution

The paper introduces a novel model based on inter-domain interactions to explain hysteresis in VO$_2$, differing from traditional Preisach models by focusing on microscopic origins.

Findings

Detection of metallic domains below hysteresis closure temperature

Identification of inter-domain interactions affecting phase transition

Development of a physical parameter-based hysteresis model

Abstract

We have performed first order reversal curve measurements of the temperature-driven metal-insulator transition in VO$_2$ thin films, which enable quantitative analysis of the hysteresis behavior. An unexpected tail-like feature in the contour plot of the reversal curve distribution indicates the existence of metallic domains, even at temperatures below the closing of the hysteresis. These domains interact with the surrounding medium and change the reversal path relative to a path from a \emph{fully} insulating state. With this in mind, and assuming that such interaction persist through the entire phase transition, we develop a model where the driving force (or energy barrier) in charge of opening a hysteresis in VO$_2$ are inter-domain interactions. This model is intrinsically different from the Preisach model usually used to describe hysteresis; given that it looks for the microscopic origin of the hysteresis, and provides physical parameters to characterize it.