Effects of oxygen annealing on magnetic properties of epitaxial PrNi0.5Mn0.5O3−δ thin films

Abstract

A series of epitaxial thin films of PrNi0.5Mn0.5O3-δ (~12 nm) were grown on single crystal LSAT [(LaAlO3)0.3(Sr2AlTaO6)0.7] substrate by pulsed laser deposition method. With a purpose to vary oxygen content in the films, the in-situ oxygen annealing time was varied (0 to 5 min)during the thin film formation. One film was not annealed after the deposition in order to create high oxygen deficiency. This oxygen-deficient film grew with a different tensile strain. In spite of oxygen variation, all the films of this series show epitaxial growth [00l] on LSAT. Temperature-dependent resistivity and magnetization measurement were performed over a temperature range of 300K to10K. All the films show insulating behavior. The temperature-dependent magnetization shows two transitions in the system finally leading to a magnetically frustrated state at low temperatures. These results indicate that Ni and Mn sub-lattices order in antiparallel spin-states in these thin films. A comparative study of magnetization in polycrystalline bulk PrMn0.5Ni0.5O3 and these thin films shows that the epitaxial strain and oxygen content strongly influences the overall magnetic behavior of this system.