Evolution and control of the phase competition morphology in a manganite film

TL;DR

This study uses magnetic force microscopy to image and analyze the sharp, cooperative phase transition from a ferromagnetic metal to a charge-ordered insulator in a manganite film, revealing diverse morphologies and controllable phase domain engineering.

Contribution

It provides direct microscopic imaging of the reverse phase transition in manganites, highlighting its sharpness, diversity, and controllability, which advances understanding of phase competition.

Findings

COI domains exhibit variable growth with temperature

The transition is sharp, cooperative, and martensitic-like

Phase domain engineering is achievable

Abstract

The competition among different phases in perovskite manganites is pronounced since their energies are very close under the interplay of charge, spin, orbital and lattice degrees of freedom. To reveal the roles of underlying interactions, many efforts have been devoted towards directly imaging phase transitions at microscopic scales. Here we show images of the charge-ordered insulator (COI) phase transition from a pure ferromagnetic metal with reducing field or increasing temperature in a strained phase-separated manganite film, using a home-built magnetic force microscope. Compared with the COI melting transition, this reverse transition is sharp, cooperative and martensitic-like with astonishingly unique yet diverse morphologies. The COI domains show variable-dimensional growth at different temperatures and their distribution can illustrate the delicate balance of the underlying interactions in manganites. Our findings also display how phase domain engineering is possible and how the phase competition can be tuned in a controllable manner.