Oxide film constricts under an electric field

Abstract

Researchers have discovered a new way to engineer thin films that change volume under an electric field. Their technique could help scientists create small, energy-efficient biomedical devices ( Nature 2022, DOI: 10.1038/s41586-022-05073-6 ). Electrostrictive materials generate strain in response to an electric field. Researchers are interested in harnessing this property, measured by a material’s electrostriction coefficient, to build low-power biomedical devices such as microsensors. But many of the highest-performing electrostrictors contain lead, which can be toxic. Recently, scientists discovered electrostriction properties in gadolinium-doped cerium oxide (CGO), which is used in solid oxide fuel cells. Materials scientists Haiwu Zhang, Nini Pryds, and Vincenzo Esposito of the Technical University of Denmark wanted to know if they could improve its performance. They started by depositing alternating layers of CGO and erbium-stabilized bismuth oxide onto a neodymium gallate substrate, making multilayer films about 17 nm thick. Chemical defects in the oxide layers create local