Temperature and pressure-induced spin-state transitions in LaCoO3

TL;DR

This study investigates how temperature and pressure induce spin-state transitions in LaCoO3, revealing a transition to an intermediate spin state with temperature and a low spin state under high pressure, using spectroscopic techniques.

Contribution

It provides detailed experimental evidence of spin-state transitions in LaCoO3 under varying temperature and pressure conditions, combining multiple spectroscopic methods.

Findings

Transition to intermediate spin state at certain temperatures

Low spin state achieved at high pressure (40-70 kbar)

Continuous redistribution of 3d electrons observed

Abstract

We report the continuous variation of the spin moment of cobalt in LaCoO3 across its temperature and pressure-induced spin transitions evidenced with K\beta emission spectra. The first thermal transition is best described by a transition to an orbitally nondegenerate intermediate spin (S=1) state. In parallel, continuous redistribution of the 3d electrons is also indicated by partial fluorescence yield X-ray absorption spectra. At high pressure, our study confirms that the material becomes low spin between 40 and 70 kbar at room temperature.