Thickness-dependent magnetotransport in ultrathin manganite films

To understand the near-interface magnetism in manganites, ultrathin films of La0.67Sr0.33MnO3 were grown epitaxially on single-crystal (001) LaAlO3 and (110) NdGaO3 substrates. The temperature and magnetic field-dependent film resistance is used to probe the film's structural and magnetic properties. A surface and/or interface related dead layer is inferred from the thickness-dependent resistance and magnetoresistance. The total thickness of the dead layer is estimated to be similar to 30 Angstrom for films on NdGaO3 and similar to 50 Angstrom for films on LaAlO3. (C) 1999 American Institute of Physics. [S0003-6951(99)02420-1].