Step-edge magnetoresistance in La0.7Ca0.3MnO3 films

The magnetoresistance of step-edge structures in La0.7Ca0.3MnO3 films was i nvestigated. Step- edge arrays with 200 steps of height 140-200 nm and step separation 20 mu m along [110] were fabricated on LaAlO3 substrates by che mically assisted ion-beam etching. Thin La0.7Ca0.3MnO3 films were deposited on the structured substrates by pulsed-laser deposition. Measurements of t he large low-field magnetoresistance, the dynamic conductance, and the anis otropic magnetoresistance lead to the proposal of a model of spin-polarized tunneling in a ferromagnet/spin-glass/ferromagnet geometry. (C) 1999 Ameri can Institute of Physics. [S0003-6951(99)04410-1].