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Heterostructure composed of electron-doped high-Tc superconductor La1.89Ce0.11CuO4 (LCCO), ferroelectric Ba0.5 Sr0.5 TiO3 (BST) and colossal magnetoresistance (CMR) La0.67 Sr0.33 MnO3 (LSMO) thin films were deposited on the (001) SrTiO3 (STO) substrate by pulsed laser deposition method. The current-voltage measurement shows that the LCCO/BST/LSMO structure has strong rectification comparing to the LCCO/LSMO, LCCO/BST and BST/LSMO bilayer structures. The experiment indicates that both the BST and LCCO layers play important roles in the rectifying effect in the oxide heterostructures. We discuss the mechanism of their rectification based on the energy band bending as well as the depletion and the diffusion of the charge carriers at the interfaces. The growth conditions and the multilayer features as well as the properties of individual material in the heterostructures were also investigated. [ABSTRACT FROM AUTHOR]

Underdoped electron-doped La2-xCexCuO4 (x=0.06-0.09) thin films were successfully grown and investigated for the transport properties in ab-plane. It was found that the in-plane resistivity ρab shows a semiconductor behavior when x=0.06, with increasing the Ce concentration to the optimal doping level, it changes to the two dimensional Fermi-liquid behavior. In the films with x≥0.08, a Kondo effect like scattering is observed in the low temperature range. [ABSTRACT FROM AUTHOR]

High quality epitaxial thin films of FeSe1-xTe_x (x=0–1) have been successfully fabricated. Their superconducting transition temperatures are around 8–13 K. Microwave properties of a film (x=0.7) was studied by a sapphire dielectric cavity at 9.315 GHz. The cavity, which has a quality factor of 45000 in room temperature with TE011-mode, is specially designed for the measurement of small samples with the sapphire cylinder having a small hole in the center. Thin film samples with dimension of 1–2 mm can be put in the middle of the hole, supported by a very thin sapphire rod. The cavity is sealed in a vacuum chamber soaked in the liquid ^4He and the temperature of the thin sapphire rod (hence the sample) can be controlled from 1.6 K to 60 K with a stability about \pm1 mK. Temperature dependence of transmission response and Q-factors were measured by a network analyser (Agilent N5230C). The results showed a clear signature of multi-gap superconductivity. No evidences of existence of node in the energy gap were found as the normalized change in the surface reactance and the corresponding normalized change in the in-plane penetration depth have flat dependence at low temperatures. [ABSTRACT FROM AUTHOR]

Epitaxial Ba0.15Zr0.85TiO3 (BZT) ferroelectric thin films with (001), (011), and (111) orientations were, respectively, grown on La0.67Sr0.33MnO3 (LSMO) buffered LaAlO3 substrates by pulsed laser deposition method. The dc electric-field dependence of permittivity and dielectric loss of (001)-, (011)-, and (111)-oriented BZT/LSMO heterostructures obeys the Johnson formula, and the ac electric-field dependence of that obeys the Rayleigh law under the subswitching field region. The anisotropic dielectric properties are attributed to the higher mobility of the charge carriers, the concentration of mobile interfacial domain walls, and boundaries in the (111)-oriental films than in the (110)- and (100)-oriented films. [ABSTRACT FROM AUTHOR]