Modulation on the magnetic and electrical transport properties of Pr0.5Ba0.5MnO3-δ thin films by oxygen vacancies

In this work, the magnetic and electronic transport properties of the epitaxial Pr0.5Ba0.5MnO3-delta (PBMO) thin films via the modulation of the oxygen vacancies have been investigated. PBMO thin films were fabricated by pulsed laser deposition (PLD) at different oxygen ambient pressures (20, 50, 70, and 250 mTorr). From the XRD and STEM measurements, the oxygen vacancies content in the film increases with the decrease of growth pressure, leading to an expansion of the out-of-plane lattice constant of the film. The PNR (Polarized Neutron Reflectometry) was employed for a precise magnetization and oxygen stoichiometry depth profile of the PBMO thin films and further quantitatively characterize the oxygen vacancies' content of the films. Thus, an increasing number of oxygen vacancies suppress the double exchange interaction and carriers hopping are suppressed, resulting in a significant increase in resistivity, as well as a decrease in saturation magnetization and ferromagnetic Curie temperature.