Lattice structure and magnetization of LaCoO3 thin films

TL;DR

This study explores how strain influences the structure and magnetic properties of LaCoO3 thin films, revealing ferromagnetism and a correlation between strain and magnetic moments, differing from bulk behavior.

Contribution

It demonstrates the tunability of LaCoO3 thin film properties via substrate-induced strain, highlighting the relationship between lattice distortion and magnetization.

Findings

Films are ferromagnetic with T_C around 85 K.

Magnetic moments are below 1 μ_B per Co3+ ion.

Strain correlates with magnetic moment variations.

Abstract

We investigate the structure and magnetic properties of thin films of the LaCoO$_{3}$ compound. Thin films are deposited by pulsed laser deposition on various substrates in order to tune the strain from compressive to tensile. Single-phase (001) oriented LaCoO$_{3}$ layers were grown on all substrates despite large misfits. The tetragonal distortion of the films covers a wide range from -2% to 2.8%. Our LaCoO$_{3}$ films are ferromagnetic with Curie temperature around 85 K, contrary to the bulk. The total magnetic moment is below $1\mu_{B}$/Co$^{3+}$, a value relatively small for an exited spin-state of the Co$^{3+}$ ions, but comparable to values reported in literature. A correlation of strain states and magnetic moment of Co$^{3+}$ ions in LaCoO$_{3}$ thin films is observed.