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通过X射线衍射、差热分析、电子显微镜、超导电性测量等手段研究了研磨对Y-123和Bi(Ph)-2223超导相和成相过程的影响。结果表明:研磨对Y-123和Bi(Ph)-2223超导相的影响显著不同,研磨导制了Bi(Ph)-2223超导相的破坏。同时指出Bi(Ph)-2223超导相同一结构特征的两种属性:好的可塑性和结构易破坏性。前者是优点,后者是缺点。在加工、测量、使用过程中,要尽力避免后一缺点带来的超导电性的破坏或由于局部结构破坏而导致的整体性能的降低。 相似文献
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本用拉伸实验的方法,在室温至78K的温度范围内,研究了Y1-xPrxBa2Cu3Oy(x分别为0,0.1,0.3,0.4和0.6)的铁弹性行为。结果表明,Tc以上几十度温度范度内与铁弹性行为有关的能量损耗分析(△W/W)以及类似于热弹性马氏体含量的形状记忆效应与类相变有关,并与超导电性有内在的联系。 相似文献
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This paper presents three different kinds of infrared (IR) spectra of oxide materials. The first one is the IR reflection spectra of Ti2Ba2Ca2Cu3O10 superconducting film at the incident angles 7°, 12° and 30°. The second one is the IR spectra of nonsuperconducting ceramic materials YBa2Cu3O6 and PrBa2Cu3O7. The third one is the IR spectra of superconductor YBa2Cu3O7-δ and of its film with the c-axis perpendicular to the film plane, as well as the changes in the spectra of these materials after annealing at different temperatures. It is found that in the spectra of high-Tc oxide superconductor, only the phonon modes along c-axis can be observed while the modes in a-b plane are absent. But in the spectra of nonsuperconductors the modes in a-b plane can be observed, particularly in the absorption spectra of the semiconductor YBa2Cu3O6, all eleven allowed IR active modes have been detected. We suggest that the above experimental phenomena may result from the fact that the phonon modes vibrating in the a-b plane of the high-Tc oxide superconducting materials are almost screened by the free carriers which can move only in a-b plane. 相似文献
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The a-axis oriented YBa2Cu3Ox(YBCO) thin films could be grown on (100) SrTiO3(STO) substrates with STO buffer layers by dc and rf magnetron sputtering either by low-ering the deposition temperature, or by using a self-template technique. For the latter, the resistivity of the thin film at 290K along the substrate [001] direction is about four times larger than that in the [010] direction. The zero resistance temperatures Tc0 are 89 K in both directions. So high quality a-axis oriented YBCO thin films can be prepared by the self-template technique. Also the Tc0 increase monotonously with the reduction of the thickness of the YBCO seed layer. 相似文献
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Single crystal growth and characterizations of iron arsenide superconductor BaFe2-xNixAs2(0.0≤x≤0.12) 下载免费PDF全文
A series of big single crystals of BaFeFe2-xNixAs2 have been prepared by the FeAs self-flux method,
with nominal nickel doping x = 0--0.12. The dimensions of the
cleaved crystals are over 10~mm along ab plane and ~ 2~mm
in maximum along the c direction. The measurements of x-ray
diffraction, electrical resistance and magnetic property are carried
out on the crystals. For the undoped parent compound
BaFe2As2, both resistance and magnetization data display
an anomaly associated with spin density wave and/or structural phase
transition, with the transition temperatures at ~ 138~K. For
Ni-doped BaFe2-xNixAs2 crystals, the
superconducting critical temperature Tc ranges from 4.3~K
for x=0.06 sample to 20~K for the optimally doped x=0.10
crystal. 相似文献