# First-Order Reversal Curves of the Magnetostructural Phase Transition in FeTe

## TL;DR

This study applies the FORC method to FeTe's magneto-structural phase transition, revealing complex features and magnetic-structural coupling that are not apparent in traditional measurements.

## Contribution

It introduces the use of FORC measurements to analyze the magneto-structural phase transition in FeTe, distinguishing magnetic and structural contributions.

## Key findings

- FORC reveals two features in the hysteretic phase transition.
- Magnetic field influences the structural and magnetic components differently.
- Uniaxial stress broadens the transition distribution without altering energy barriers.

## Abstract

We apply the first-order reversal curve (FORC) method, borrowed from studies of ferromagnetic materials, to the magneto-structural phase transition of FeTe. FORC measurements reveal two features in the hysteretic phase transition, even in samples where traditional temperature measurements display only a single transition. For Fe1.13Te, the influence of magnetic field suggests that the main feature is primarily structural while a smaller, slightly higher-temperature transition is magnetic in origin. By contrast Fe1.03Te has a single transition which shows a uniform response to magnetic field, indicating a stronger coupling of the magnetic and structural phase transitions. We also introduce uniaxial stress, which spreads the distribution width without changing the underlying energy barrier of the transformation. The work shows how FORC can help disentangle the roles of the magnetic and structural phase transitions in FeTe.