Electric-pulse induced resistance hysteresis switching loops for Pr0.7Ca0.3MnO3 perovskite oxide films were found to exhibit an additional sharp "shuttle tail" peak around the negative pulse maximum for films deposited in an oxygen-deficient ambient. The resistance relaxation in time of this "shuttle tail" peak as well as resistance relaxation in the transition regions of the resistance hysteresis loop show evidence of oxygen diffusion under electric pulsing, and support a proposed oxygen diffusion model with oxygen vacancy pileup at the metal electrode interface region as the active process for the nonvolatile resistance switching effect in transition-metal oxides.

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Anisotropic in-plane strain can be induced in (Pb,Sr)TiO3 (PST) thin film by using orthorhombic NdGaO3 (110) as a substrate. High-resolution x-ray diffraction was used to measure the strain of the PST thin film. A rocking curve with full width at half maximum of ∼0.04° illustrated that the film had nearly perfect single-crystalline quality. Reciprocal space maps around the (001), (103), and (013) reflections of the PST film revealed anisotropic in-plane strain of 485 ppm along [100] and 26 ppm along [010], respectively. Coplanar capacitance measurements also showed systematic changes in the dielectric constant and tunability due to strain; about a 15% difference in tunability at surface field of 50 kV/cm and a 20% difference in the zero-field dielectric constant were observed along [100] and [010], respectively.

Recent research on the resistance switching effect in manganite oxide based electric-pulse-induced resistance (EPIR) devices is being reviewed. The EPIR effect encompasses the reversible change of resistance of a thin oxide film such as Pr 1-x Ca x MnO 3 (PCMO) under the application of short, low voltage pulses. Two groups of EPIR devices have been investigated: one with the PCMO layer sandwiched between a top and a bottom electrode; the other with both electrodes on top of the PCMO thin films, which were grown on insulating substrates. I-V switching characteristics, electric pulse switching hysteresis, as well as the dynamic resistance during nano second switching pulses of the EPIR devices were measured. Temperature studies showed similar activation energies for both high and low resistance states. Resistance profile microanalysis showed resistance switching both in the interface regions of the oxide film near the electrode, as well as in the bulk of PCMO film with the major resistance change from the interface regions. The resistance switching mechanism is discussed.

Raman spectra of LCMO films grown on LAO (001), STO (001), and MgO (001) substrates were studied at different temperatures. The effect of temperature, doping level and strain on Raman spectra are discussed in detail. With decreasing temperature, the changes of Raman spectra are correlated with the disorder-order transition, shuch as: paramagnetism to ferromagnetism, and chargeordering. The strain induced by lattice-substrate mismatch affects the Raman spectra strongly. The mode induced by disorder of oxygen defects is apparently observed in La0.67Ca0.33M nO3 film on STO due to the larger tensile strain. While this mode can not be seen in the Raman spectra for the films on LAO and MgO. A strong unsigned mode at about 690 cm −1 is observed in all films except for La0.67Ca0.33M nO3 film on LAO, which is not observed in bulk sample easily. It suggests that the mode is closely related to the strain.

Articles you may be interested inEffect of stoichiometry on the dielectric properties and soft mode behavior of strained epitaxial SrTiO3 thin films on DyScO3 substrates Appl. Phys. Lett. 102, 082905 (2013); 10.1063/1.4793649In-plane dielectric properties of epitaxial Ba0.7Sr0.3TiO3 thin films grown on GaAs for tunable device application

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