Multi-messenger nano-probes of hidden magnetism in a strained manganite

TL;DR

This study demonstrates a reversible, photoinduced ferromagnetic transition in strained manganite films, utilizing advanced multi-messenger microscopy techniques to control and understand nanoscale magnetic phases.

Contribution

It introduces a novel multi-messenger approach to manipulate and analyze metastable magnetic phases in strained manganites at the nanoscale, combining experimental and theoretical insights.

Findings

Reversible photoinduced ferromagnetic transition observed.

Strain underpins the stability and reversibility of the magnetic phase.

First-principles calculations reveal strain-stabilized electronic phases.

Abstract

The ground state properties of correlated electron systems can be extraordinarily sensitive to external stimuli, such as temperature, strain, and electromagnetic fields, offering abundant platforms for functional materials. We present a metastable and reversible photoinduced ferromagnetic transition in strained films of the doped manganite La(2/3)Ca(1/3)MnO3. Using the novel multi-messenger combination of atomic force microscopy, cryogenic scanning near-field optical microscopy, magnetic force microscopy, and ultrafast laser excitation, we demonstrate both "writing" and "erasing" of a metastable ferromagnetic metal phase with nanometer-resolved finesse. By tracking both optical conductivity and magnetism at the nano-scale, we reveal how spontaneous strain underlies the thermal stability, persistence, and reversal of this photoinduced metal. Our first-principles electronic structure calculations reveal how an epitaxially engineered Jahn-Teller distortion can stabilize nearly degenerate antiferromagnetic insulator and ferromagnetic metal phases. We propose a Ginzburg-Landau description to rationalize the co-active interplay of strain, lattice distortion, and magnetism we resolve in strained LCMO, thus guiding future functional engineering of epitaxial oxides like manganites into the regime of phase-programmable materials.