Cation uniformity and magnetic properties of La0.7Sr0.3Mn0.5Fe0.5O3 thin films

In this paper, we report on the effect of the target–substrate distance during pulsed laser deposition on the uniformity of the cation distribution in La0.7Sr0.3Mn0.5Fe0.5O3 (LSMFO) thin films. Through a combination of x-ray diffraction, atomic scale scanning transmission electron microscopy, and soft x-ray magnetic spectroscopy, the microstructure and magnetic properties were characterized in detail and correlated to one another. With a large target–substrate distance, cation segregation occurred such that the Mn and Fe ions were found in mixed valence states and coordination environments. As a consequence, an unexpected ferrimagnetic ordering in the LSMFO films was observed. Uniformly cation-distributed thin films could be deposited with smaller target–substrate distance, and no such magnetic ordering was observed. This difference is discussed in the context of the kinetic energy of the plume considering the interaction of the plume species with the background O2 gas molecules.