Martensitic transformations in VO2 films

Abstract Martensitic transformation is considered to be non-diffusive since the atoms in the transition are moved to a distance of the order of interatomic, and neighboring atoms in the initial phase remain adjacent and in the new one, only their position changes. In this paper, for the first time, an experimental study of the phase transition metal-dielectric (FPMD) in thin films of vanadium dioxide is accompanied by a structural transition of martensitic type, so this material is a convenient model object that allows you to clearly identify both the processes of defect formation and their influence on its physical properties in the vicinity of the phase transition point. The obtained results are naturally associated with the effect of adhesion and epitaxy on the phase transition, which can be reduced to the contribution to the energy balance of the component σ/d, where σ is the density of the surface energy; d is the film thickness. Physically, this may mean that since the growth of films occurs at a temperature above the FPMD temperature, the orientation of the crystal axes of the high-temperature tetragonal phase is stabilized by epitaxial forces from the substrate side, and this makes it difficult to reconstruct the crystal structure during the phase transition. Phase stabilization in thin layers due to surface effects is a common phenomenon in the physics of thin films.

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