Influence of the interface in quantum corrections on the low-temperature resistance of La(2/3)Sr(1/3)MnO3 trilayer masking thin films.

We report the low-temperature resistance upturn in sandwiched structures of La2/3Sr1/3MnO3/ZrO2/La2/3Sr1/3MnO3 and La2/3Sr1/3MnO3/LaMnO3/La2/3Sr1/3MnO3, while it disappeared when the interlayer was replaced by YBa2Cu3O7. The experimental data have been analyzed qualitatively and quantitatively. The results show that the low temperature resistance upturn is mainly due to the quantum correction effects driven by the weak localization and the electron-electron interaction in such a strongly correlated system, and the contribution of each factor varies with grain boundaries. Moreover, the resistance upturns are suppressed by a local magnetic field. These findings will help to further understand the physical mechanism of low-temperature resistance upturn in colossal magnetoresistance manganites. Furthermore, it is also helpful to reveal the intrinsic transport mechanism at the interfaces of semiconductor/ferromagnetism and antiferromagnetism/ferromagnetism.

Semiconductor/Piezoelectrics Hybrid Heterostructures with Highly Effective Gate-Tunable Electrotransport and Magnetic Behaviors.

We report the epitaxial growth of oxygen deficient titanium dioxide thin films on 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) single crystals and realized highly effective in situ electrostatic manipulation of electrotransport and magnetism of TiO2-δ films via gate voltages. Upon the polarization switching in the PMN-PT, the carrier density of the TiO2-δ film could be reversibly modified, resulting in a large nonvolatile resistivity modulation by ∼51% at T = 300 K, approximately 4-12 times larger than that of other transition-metal oxide film/PMN-PT structures. By taking advantage of in situ manipulation of the carrier density via gate voltages, we found that competition between the trap of electrons by the Ti3+-VO pairs and that by the positive polarization charges at the interface results in a significant resistivity relaxation upon the polarization switching, and revealed that magnetization is inversely correlated with the carrier density of the TiO2-δ film. Such hybrid structures combining materials with dissimilar functionalities may have potential applications in multifunctional devices which can take advantage of the useful and unique properties of both materials.