Dynamic chemical expansion of thin-film non-stoichiometric oxides at extreme temperatures

• Main Authors: Smith, James F. (Author), Swallow, Jessica Gabrielle (Contributor), Kim, Jae Jin (Contributor), Maloney, John (Contributor), Chen, Di (Contributor), Bishop, Sean (Contributor), Tuller, Harry L (Contributor), Van Vliet, Krystyn J (Contributor)
• Other Authors: MIT Materials Research Laboratory (Contributor), Massachusetts Institute of Technology. Department of Materials Science and Engineering (Contributor), Vliet, Krystyn Van J. (Contributor)
• Format: Article
• Language: English
• Published: Springer Nature, 2017-12-07T19:16:40Z.
• Subjects: Article
• Online Access: Get fulltext

 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.