Effect of magnetic film thickness on rectifying properties of La0.8Sr0.2MnO3/TiO2 heterostructures

The La_0.8Sr_0.2MnO₃ (LSMO)/ TiO₂ heterostructures with different thicknesses of the LSMO films were successfully synthesized using the RF magnetron sputtering technique. Excellent rectifying characteristics are presented in all heterostructures in a wide temperature range. The differences of the diffusive potentials for three heterojunctions are very little at 300 K. The samples exhibit a high resistance that plays an important role on their rectifying properties. The diffusive potential decreases with increasing temperature. The result is attributed to both the reduction of the thickness of the deletion layer due to the thermal diffusion and the modulation of the interfacial electronic structure of the heterostructures. The metal-insulator (M-I) transition is observed clearly from the single LSMO layers and the LSMO/ TiO₂ p-n heterojunctions.