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Zhou M.,Northwest Normal University | Sun A.,Northwest Normal University | Sun A.,Chinese Academy of Sciences | Sun A.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | And 2 more authors.
Superconductor Science and Technology | Year: 2013

A series of polycrystalline YBa2Cu3O 7-δ (YBCO) + x mol% Y2Ba4CuMoO y (Y-24Mo1) (x = 0.00, 0.05, 0.10, 0.20, 0.30, 0.50, 2.00 and 3.00) superconductors have been synthesized in air via a standard solid-state reaction technique. The effects of Y-24Mo1 addition on the microstructure, elemental distribution and the superconducting transition temperature were systematically investigated. When Y-24Mo1 was added to the YBCO, the predominantly single-phase with orthorhombic structure was maintained even at the highest concentration. SEM, EDS and EELS analyses show the presence of inhomogeneities, the change of homogeneity and the variation of oxygen distribution in the superconducting matrix. The Y-24Mo1 addition modifies the normal-state resistivity of samples from metallic to semiconducting, and is accompanied by a two-step transition. Moreover, low Y-24Mo1 concentration leads to a relatively sharp superconducting transition and a broad transition takes place for Y-24Mo1 addition greater than 0.30 mol%. These results can be interpreted by the change of oxygen distribution and by the variation of defects, twins, and oxygen deficiency. © 2013 IOP Publishing Ltd. Source


Ma L.-G.,Northwest Normal University | Ma S.-Y.,Northwest Normal University | Ma S.-Y.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | Chen H.-X.,Northwest Normal University | Huang X.-L.,Northwest Normal University
Gongneng Cailiao/Journal of Functional Materials | Year: 2011

The Al-doped ZnO (AZO) thin films with different Al contents were deposited on ZnO buffer layer by reactive RF magnetron sputtering technology.The microstructure, surface morphology, luminescence properties of the AZO thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM)and photoluminescence (PL) spectrum, respectively.The results revealed that the preferred orientation of ZnO films became with increasing Al doping concentration.And as Al doping concentration was 0.81at% the ratio of intensity of (002) to other peaks attained maximum, which indicated that appropriate Al-doping can improve the preferred orientation of ZnO films.The average transmittance was above 70%in the visible range.Two blue peaks located at 444nm (2.80eV) and 483nm (2.57eV) and weak green peak located at about 521nm (2.38eV) were observed from the PL spectra of the four samples and the mechanism of luminescence was discussed. Source


Jia R.-J.,Northwest Normal University | Wang C.-L.,Northwest Normal University | Yang Y.,Northwest Normal University | Gou X.-Q.,Northwest Normal University | And 3 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2013

Locked-to-sliding phase transition is studied based on the two-dimensional Frenkel-Kontorova model in this paper. The method of molecular dynamics simulation is used. The effect of the static friction force on system parameter is investigated numerically when the upper layer atoms are of the hexagon symmetric structure. © 2013 Chinese Physical Society. Source


Zhou M.,Northwest Normal University | Sun A.,Northwest Normal University | Sun A.,Chinese Academy of Sciences | Sun A.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | And 3 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2014

Synthesis of polycrystalline YBa2Cu3O 7-δ (YBCO) + x mol.% Y2Ba4CuMoO y (Y-24Mo1) (x=0.0, 0.1, 0.2, 1.0, 2.0 and 20.0) superconductors have been done in air via a standard solid state reaction technique. The effects of Y-24Mo1 particles on the microstructure and the superconducting transition temperature were systematically investigated through XRD and SEM techniques. When Y-24Mo1 was added to the YBCO, the orthorhombic structure maintained even at the highest concentration. Tiny peaks of Y-24Mo1 having (022) orientation and some other impurity were detected in the XRD spectrum when x=20.0. SEM results reveal the presence of some entities, and these entities changed with increase of Y-24Mo1 content. The Y-24Mo1 addition modifies the normal state resistivity of samples from metallic to semiconducting, and is accompanied by a two-step transition. Moreover, low Y-24Mo1 concentration leads to a relatively sharp superconducting transition and a broad transition take place for Y-24Mo1 addition greater than 0.2 mol.%. These results can be induced by the inhomogeneities, by the change of the effective coupling strength, and by the variation of the coupling between grains. © 2013 Springer Science+Business Media New York. Source


Yang Y.,Northwest Normal University | Wang C.-L.,Northwest Normal University | Duan W.-S.,Northwest Normal University | Duan W.-S.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | And 2 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2012

In order to better simulate a real model which can be realized in experiment, we study a two-dimensional(2D) Frenkel- Kontorova(FK) model driven by the disordered substrate potential which is charactered by the sum of identical Gaussian functions. Commensurate and incommensurate interfaces are discussed. In the paper, we mainly analyse the mechanism of friction, and the effects of static friction force on the disordered substrate potential. © Chinese Physical Society. Source

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