Room temperature magnetic transition in nanoparticles films of Pr0.5Sr0.5MnO3 produced by pulsed laser deposition

We report the synthesis of Pr0.5Sr0.5MnO3 nanoparticles (NPs) by pulsed laser deposition (PLD) with varying energy per pulse (100, 200 and 300 mJ) under Ar (Argon) atmosphere. We have obtained NPs with average diameters of 10, 16, 19 nm, with narrow size distribution and core-shell morphology, in which the cores are crystalline and the shells amorphous. Due to the large amount of amorphous phase, heat treatment at temperatures of 750 and 900 °C was applied and X-ray diffraction with Rietveld refinement analyses indicated that highly crystalline PSMO NPs were obtained with an average diameter of 35 nm and 65 nm, respectively. Note that the annealing was also useful to tune the NPs size. Target magnetic investigation indicated that the Pr3+ and Mn3+/Mn4+ magnetic sublattices couple in an antiferromagnetic (AFM) fashion at low temperatures, undergoing a reversible transition to the ferromagnetic (FM) state around 200 K. However, heat-treated NPs behave differently – the ZFC and FC curves exhibit an irreversibility that is most likely associated with the weakening of AFM interactions on the surface of the NPs. Despite this characteristic, the NPs exhibit a sharp magnetic transition (FM-PM) with TC around 300 K, which makes these NPs useful candidates for magnetocaloric, magnetoresistivity and medicine applications.