Improved electrical properties of La2/3Ba1/3MnO3:Ag0.04 thin films by thermal annealing

La2/3Ba1/3MnO3:Ag0.04 (LBMO:Ag0.04) thin films were prepared on single crystalline (001)-orientated LaAlO3 substrates by pulsed laser deposition technique. Thermal annealing with temperatures of 780, 800 and 820 °C has been investigated to improve electrical properties of the films. All the samples are shown along the (00l) orientation in rhombohedral structure with R3¯c\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ R\overline{3} c $$\end{document} space group. With thermal annealing temperature increasing, insulator–metal transition temperature (Tp) and resistivity at Tp (ρTp\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \rho_{{T_{\text{p}} }} $$\end{document}) of the epilayer reach optimal value of 288 K and 0.03 Ω·cm, respectively. The electrical properties improvement of the LBMO:Ag0.04 films is due to an improved film crystallization, oxygen balance and photon scattering suppression. The fitting curves show that the region of ferro-magnetic metallic (FM, T < Tp) is fitted with grain/domain boundary, electron–electron and magnon scattering mechanism, as well as the region of para-magnetic insulating (PI, T > Tp) is fitted with adiabatic small polaron hopping mechanism.