Deviation from bulk in the pressure-temperature phase diagram of V2O3 thin films

• DOI: 10.1103/physrevb.95.155132
• Publication Date: 2017-04-18T22:08:46Z
• Authors: I. Valmianski; Juan Gabriel Ramirez; C. Urban; X. Batlle; Ivan K. Schuller
• Keywords: Hydrostatic pressure

We found atypical pressure dependence in the transport measurements of metal to insulator transition (MIT) epitaxial thin films vanadium sesquioxide (${\mathrm{V}}_{2}{\mathrm{O}}_{3}$). Three different crystallographic orientations and four thicknesses, ranging from 40 500 nm, were examined under hydrostatic pressures $({\mathrm{P}}_{h})$ up 1.5 GPa. All at exhibited a order magnitude resistance change, with temperatures 140 165 K, depending on orientation. This allowed us build pressure-temperature phase diagrams several film thicknesses. Interestingly, for below MPa, all samples deviate bulk behavior show weak temperature $({T}_{c})$ $(d{T}_{c}/d{P}_{h}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0.16em}{0ex}}0.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}\phantom{\rule{0.28em}{0ex}}\mathrm{K}/\mathrm{MPa}),$ which recovers bulklike $(3.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0.16em}{0ex}}0.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}\phantom{\rule{0.28em}{0ex}}\mathrm{K}/\mathrm{MPa})$ higher pressures. Furthermore, we that pressurization leads morphological but not structural changes films. indicates difference is most probably due pressure-induced grain boundary relaxation, as well both plastic elastic deformations microstructure. These results highlight between behaviors.