Oxygen diffusion in La2/3Ga1/3MnO3 and Sr2FeMoO6 thin films

Abstract

Thin films of colossal magnetoresistance La0.67Ca0.33MnO3 (LCMO) (d=200+300 nm), highly conductive LaNiO3 (LNO) (150+200 nm), double perovskite Sr2FeMoO6 (SFMO) (congruent to 70 nm) as well as LCMO/LNO bilayers were grown heteroepitaxially by dc magnetron sputtering and pulsed laser deposition on lattice- matched NdGaO3(100) and SrTiO3(100) to investigate oxygen diffusion in LCMO, LNO and SFMO, In-situ electrical resistance measurements were performed at (78 1000) K in vacuum (p congruent to 10(-4) Pa) and oxygen gas (p congruent to 105 Pa) by varying temperature of the films linearly with time: T(t)=T- 0+/-beta t. The activation energy of oxygen ion diffusion, E-D, of 1.3 eV and 1.2 eV have been estimated for the LCMO and LNO films, respectively, by fitting numerical and experimental data. Unusual resistance changes of the Sr2FeMoO6 thin films during their annealing in oxygen at Tgreater than or equal to500 K had showed formation of high resistance regions in the vicinity of grain boundaries.