# Influence of misfit dislocations on the phase transition of iron(iii) oxides

## TL;DR

This paper explores how misfit dislocations affect the phase transition of iron(III) oxide thin films as their thickness changes.

## Contribution

The study identifies a critical thickness threshold and links phase transitions in Fe2O3 to misfit dislocation formation.

## Key findings

- The ε-Fe2O3 phase is stabilized in films thinner than 20 nm.
- Above 20 nm, ε-Fe2O3 transforms into α-Fe2O3 due to misfit dislocations.
- Misfit dislocations at the film/substrate interface compensate for tensile strain.

## Abstract

Dislocations commonly occur in thin films under large misfit strain due to the accumulation of strain energy, significantly altering the films' properties. This study investigates the microstructure of Fe2O3 polymorphs in films of various thicknesses deposited on yttria-stabilized zirconia (001) substrates. The results reveal that the ε-Fe2O3 phase is formed and stabilized at thicknesses below a critical threshold of 20 nm. Beyond this threshold, the volume fraction of the ε-Fe2O3 phase decreases, and the α-Fe2O3 phase begins to emerge. With further increases in thickness, the ε-Fe2O3 phase fully transforms into the α-Fe2O3 phase. Detailed analysis suggests that this phase transformation is driven by the formation of misfit dislocations at the film/substrate interface, which compensates for the tensile strain induced by the substrate.

Dislocations commonly occur in thin films under large misfit strain due to the accumulation of strain energy, significantly altering the films' properties.