Resistance-Strain Relation On Vanadium Dioxide Thin Films

Vanadium dioxide is a strongly correlated material with a sharp metal to insulator transition at \textasciitilde 341 K. It is well known that the strain along c-axis can change the transition temperature, but the other effects of the strain have not been drawing much attention. In this work we have studied the effects of the strain on resistance changes in the polycrystalline and epitaxial films. Polycrystalline films of VO$_{\mathrm{2}}$ are deposited on the Pb(Mg1/3Nb2/3)0.72Ti0.28O3(001) (PMN-PT) using a SiO$_{\mathrm{2}}$ buffer layer. The strain on film is tuned by applying a bias electric field through the piezoelectric substrate, and the resistance is measured using four-probe method. The epitaxial films of VO$_{\mathrm{2}}$ are grown on TiO$_{\mathrm{2}}$ (001) and have been glued to PMN-PT substrate to transfer strain. The change in the resistance of the epitaxial films is measured to be only about 30{\%} more than polycrystalline films for the same amount of strain. We have studied the strain-induced resistance changes as a function of temperature. we have shown that the resistance is more sensitive to strain in the metallic phase.