In situ probing the heating effect and phase transition in perovskite heterostructures

Perovskite oxide heterostructures exhibit a series of correlated electronic functionalities, associated with the coupling among the lattice, charge, spin and orbital orderings. As a fundamental thermodynamic parameter, temperature measurement is critical to both fundamental research and practical devices. To date, most of temperature sensing for heterostructures are based on electrical resistance-based thermometry. However, they are sensitive to environmental conditions as well as electromagnetic interference, and are impractical in harsh environments or close systems due to the direct contact operation mode. Contactless optical thermometry based on lanthanide luminescence appears as a promising alternative technique, and aims to bypass abovementioned limitations. Herein, we propose a reliable fluorescence intensity ratio-type optical thermometer based on the thermally coupled energy levels of Er3+, which allows remote probing the temperature variation in a series of perovskite heterostructures. Especially, the proposed optical thermometry also enables in-situ characterization of phase transition occurred in the perovskite heterostructures. Our work demonstrates the great potential of optical thermometry in the exploration of thermal phenomena in perovskite oxide heterostructures.(c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).