Magnetic and electronic structure of ultrathin La1-xSrxMnO3 films at half doping.

The magnetic, transport, and electronic properties of ultrathin epitaxial La1-xSrxMnO3 (LSMO) films at near half doping (x = 0.47, 0.50, and 0.55), grown under different misfit strains on SrTiO3(001) and La0.18Sr0.82Al0.59Ta0.41O3(001) (LSAT) substrates, are investigated. We find that all films exhibit metallic behavior below the magnetic critical temperature, while the magnetic properties change markedly with both doping and strain. However, while increased doping favors antiferromagnetic ordering, strain is the driving mechanism for the change in the magnetic properties, where with increasing tensile strain the magnetic ground state changes from ferromagnetic to antiferromagnetic at a critical lattice misfit threshold of about -1%. The bulk magnetometry data are confirmed by x-ray magnetic circular dichroism spectroscopy, while x-ray magnetic linear dichroism measured at room temperature demonstrates a progressive change in the orbital occupancy with increasing misfit strain from out of plane to in-plane, leading to a preferred antiferromagnetic metallic state at larger tensile strains. [ABSTRACT FROM AUTHOR]