The suppression of structural phase transformation in $LaVO_{3}$ and $La_{1-x}Sr_{x}VO_{3}$ thin films fabricated by pulsed laser deposition

Abstract

Highly oriented (100) thin films of $LaVO_{3}$ and $La_{1-x}Sr_{x}VO_{3}$ have been fabricated by pulsed laser deposition in a reducing atmosphere. The films show a transition from insulating to metallic behaviour in the composition region of x, 0.175 < x < 0.200. In the single crystals of the antiferromagnetic insulating phase, a first-order structural phase transition is observed few degrees below the magnetic transition, which manifests itself as a kink in the temperature dependence of resistivity. In the highly oriented thin films of $LaVO_{3}$ and $La_{1-x}Sr_{x}VO_{3}$ fabricated on lattice matched substrates in this study, the structural phase transformation in the insulating phase has been suppressed. The electrical conduction is found to take place via hopping through localized states at low temperatures. The metallic compositions show a non-linear $(T^{1.5})$ behaviour in the temperature dependence of resistivity. V (2p) core level spectra of these films show a gradual change in the relative intensities of $V^{3+}$ and $V^{4+}$ ions as the value of x increases