Measurement of thermal conductance of La0.7Sr0.3MnO3 thin films deposited on SrTiO3 and MgO substrates

•LSMO thin films are deposited on SrTiO3 or MgO substrates.•A thermal conductance model of LSMO thin films on substrate is proposed.•Model and measurements are consistent in a large frequency range.•Thermal boundary conductances of LSMO films on SrTiO3 or MgO substrates are given.•Infrared bolometers can be fabricated using LSMO on SrTiO3 or MgO substrates. We present measurements of the thermal conductance of thin-film-on-substrate structures that could serve as thin film uncooled bolometers. Studied samples were 75nm thick epitaxial La0.7Sr0.3MnO3 thin films deposited on SrTiO3 (001) and MgO (001) substrates patterned in square geometries of areas ranging from 50μm×50μm to 200μm×200μm. The model allows estimating thermal boundary conductance values at the interface between film and substrate of 0.28±0.08×106WK−1m−2 for LSMO/STO (001) and 5.8±3.0×106WK−1m−2 for LSMO/MgO (001) from measurements performed in the static regime. Analytical expressions of thermal conductance and thermal capacitance versus modulation frequency are compared to measurements of the elevation temperature due to absorbed incoming optical power. The overall good agreement found between measurements and model finally provides the possibility to calculate the bolometric response of thin film bolometers, thus predicting their frequency response for various geometries.