Dynamic chemical expansion of thin-film non-stoichiometric oxides at extreme temperatures
Author(s)Smith, James F.; Swallow, Jessica Gabrielle; Kim, Jae Jin; Maloney, John; Chen, Di; Bishop, Sean; Tuller, Harry L; Van Vliet, Krystyn J; ... Show more Show less
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Actuator operation in increasingly extreme and remote conditions requires materials that reliably sense and actuate at elevated temperatures, and over a range of gas environments. Design of such materials will rely on high-temperature, high-resolution approaches for characterizing material actuation in situ. Here, we demonstrate a novel type of high-temperature, low-voltage electromechanical oxide actuator based on the model material Pr[subscript x]Ce[subscript 1−x]O[subscript 2−δ] (PCO). Chemical strain and interfacial stress resulted from electrochemically pumping oxygen into or out of PCO films, leading to measurable film volume changes due to chemical expansion. At 650 °C, nanometre-scale displacement and strain of >0.1% were achieved with electrical bias values <0.1 V, low compared to piezoelectrically driven actuators, with strain amplified fivefold by stress-induced structural deflection. This operando measurement of films ‘breathing’ at second-scale temporal resolution also enabled detailed identification of the controlling kinetics of this response, and can be extended to other electrochemomechanically coupled oxide films at extreme temperatures.
DepartmentMIT Materials Research Laboratory; Massachusetts Institute of Technology. Department of Materials Science and Engineering
Swallow, Jessica G. et al. “Dynamic Chemical Expansion of Thin-Film Non-Stoichiometric Oxides at Extreme Temperatures.” Nature Materials (May 2017): 4898 © 2017 Macmillan Publishers Limited, part of Springer Nature
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