Role of A-site deficiency in the magneto-transport properties of Pr0.7Sr0.3MnO3 relaxed films

The magneto-transport properties of thick relaxed A-site deficient films having the composition Pr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$_{0.6}\square_{0.1}$\end{document}Sr0.3MnO3 (P□SMO with the □ symbol for the Pr vacancy) and Pr0.7Sr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$_{0.2}\square_{0.1}$\end{document}MnO3 (PS□MO) are studied. A direct comparison with a Pr0.7Sr0.3MnO3 (PSMO)completely relaxed film, deposited under the same growth conditions, shows a reduction of the in-plane parameter a100 associated to an enhancement of the out-plane parameter. The strains (bulk strain εB and biaxial Jahn-Teller strain εJ-T) do vary with the nature of the cationic vacancy. For example, an enhancement of εB of 9% in the PS□MO film (Sr deficient) produces a decrease of TC of 30 K, whereas the Pr deficient P□SMO film exhibits a large reduction of both εB (-16%) and εJ-T (divided by a factor of 5), which enhances TC of 12 K, similarly to previous observations on bulk ceramics. With a reduced resistivity (ρ<0.02 Ω cm), the obtained Pr-deficient film, P□SMO, exhibits the best magneto-transport properties with a decreasing magnetoresistance sensitivity at low field.