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 ∼30 A for films on NdGaO3 and ∼50 A for films on LaAlO3.