Effect of Co Doping on the Superconducting Properties of Overdoped (Lu0.8Ca0.2)Ba2Cu3Oz

High-Tcsuperconducting cuprates (HTSC) such as YBa2Cu3O7 − x(YBCO) are promising candidates for solid-state THz applications based on stacks of intrinsic Josephson junctions (IJJs) with atomic thickness. In view of future exploitation of IJJs, high-quality superconducting YBCO tape-like single crystals (whiskers) have been synthesized from Ca–Al-doped precursors in the presence of Te. The main aim of this paper is to determine the importance of the simultaneous use of Al, Te and Ca in promoting YBCO whiskers growth with good superconducting properties (Tc= 79–84 K). Further, single-crystal X-ray diffraction (SC-XRD) refinements of tetragonal YBCO whiskers (P4/mmm) are reported to fill the literature lack of YBCO structure investigations. All the as-grown whiskers have also been investigated by means of X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Our results demonstrate that the interplay of Ca, Te and Al elements is clearly necessary in order to obtain superconducting YBCO whiskers. The data obtained from SC-XRD analyses confirm the highly crystalline nature of the whiskers grown. Ca and Al enter the structure by replacing the Y and the octahedral coordinated Cu1 site, respectively, as in other similar orthorhombic compounds, while Te does not enter the structure of whiskers but its presence in the precursor is essential to the growth of the crystals.

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A significant improvement in the superconducting properties of MgB2 by co-doping with graphene and nano-SiC

Scripta Materialia ◽

10.1016/j.scriptamat.2012.07.014 ◽

2012 ◽

Vol 67 (10) ◽

pp. 802-805 ◽

Cited By ~ 13

Author(s):

K.S.B. De Silva ◽

X. Xu ◽

X.L. Wang ◽

D. Wexler ◽

D. Attard ◽

...

Keyword(s):

Superconducting Properties ◽

Co Doping

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Effect of Co Doping on the Superconducting Properties of Overdoped (Lu0.8Ca0.2)Ba2Cu3Oz

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.47.108 ◽

2006 ◽

Vol 47 ◽

pp. 108-112 ◽

Cited By ~ 2

Author(s):

Ho Keun Lee

Keyword(s):

Thermoelectric Power ◽

Room Temperature ◽

Oxygen Depletion ◽

Thermal Treatments ◽

Superconducting Properties ◽

X Ray Diffraction ◽

X Ray ◽

Co Doping ◽

Heat Treated ◽

Power Measurements

The effect of Co-doping and thermal treatments on the superconducting properties of the heavily overdoped (Lu0.8Ca0.2)Ba2Cu3Oz has been investigated by X-ray diffraction, resistivity and thermoelectric power measurements. A comparative analysis of the resistivity and thermoelectric power of the (Lu0.8Ca0.2)Ba2(Cu3-xCox)Oz and the heat-treated Co-free (Lu0.8Ca0.2)Ba2Cu3Oz reveals that, in the overdoped region, the hole carriers reduced by the Co doping and by the oxygen depletion play a very similar role in the superconducting properties. As a result, a nearly common inverted parabolic correlation is observed between Tc and the planar carrier concentration determined from the room-temperature thermoelectric power measurements.

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