In situ thermo-mechanical bending behavior of VO2 microcantilevers across the phase transition

Small-scale thermomechanical bending response of VO2 microcantilever has been investigated at different temperatures across the phase transition using multipoint bending protocol in a nanoindentation system. The well-defined and sharp insulator to metallic transition was captured by R-T and DSC plots prior to the microcantilever bending experiments. Load-deflection curves were obtained before and after the phase transition temperature of phase change material by applying load at a point with systematic variation in distance from fixed end of cantilever. Temperature dependent spring constant of different phases for VO2 microbeam, anchored at one end have been estimated from the measured cantilever deflection values using Euler-Bernoulli beam theory. Spring constant of the microcantilever was found to be increased by a factor of 1.3 during the structural phase transition (SPT) of VO2 from monoclinic to rutile structures. The studied bending behavior of VO2 across the phase transition with large changes in stiffness values are important for understanding the mechanical response for improving the design towards efficient cantilever and MEMS devices.