Absence of long-range Ni∕Mn ordering in ferromagnetic La2NiMnO6 thin films

Abstract

Epitaxial La2NiMnO6 thin films have been grown on (001)-orientated SrTiO3 using the pulsed laser deposition technique. The thin film samples are semiconducting and ferromagnetic with a Curie temperature close to 270K, a coercive field of 920Oe, and a saturation magnetization of 4.85μB/formula unit. Transmission electron microscopy, conducted at room temperature, reveals a majority phase having an “I-centered” structure with a≈c≈asub2 and b≈2asub along with minority phase domains having a “P-type” structure (asub being the lattice parameter of the cubic perovskite structure). A discussion on the absence of Ni∕Mn long-range ordering, in light of recent literature on the ordered double-perovskite La2NiMnO6 is presented.