Structural, electronic, and magnetic properties of double perovskite Pb2 FeReO6 thin films with (001) orientation and three possible terminations

Abstract

The structural, electronic, and magnetic properties of the three possible terminated (001)-oriented thin films of the double perovskite Pb2FeReO6 compound, 9-L FeReO4 terminated, 10-L FeReO4+PbO terminated, and 11-L PbO terminated, have been studied by using the first-principles calculations. An outward relaxation is observed for several layers near surface, and the relaxed fractional rumpling s of the PbO layer is larger than that of the adjacent FeReO4 layer, and both have a decrease tend from surface layer to inner layer. The O atom is closer to the adjacent Re atom than to the adjacent Fe atom. Except for Fe or Re transition-metal (TM) atoms on the film's symmetrical central layer, the two axial TM-O bond lengths are not equal in the survived FeO6 or ReO6 octahedra. The maintained HM-FM character ensures the three possible terminated (001)-oriented thin films of the double perovskite Pb2FeReO6 compound a potential application in magnetoresistive and spintronics devices. An FM coupling is obtained within each Fe or Re TM sublattice, whereas two TM sublattices are coupled AFM. The delocalized distribution of the spin/magnetic charge densities around the Fe atom on the first FeReO4 layer leads to a smaller magnetic moment. The remained two Re 5d2 electrons are mainly located on the down-spin t2g (dxy, dyz, and dzx) orbitals.