Evidence for two distinct orthorhombic structures associated with different Tc regimes in LnBa2Cu3O7 − δ (Ln = Nd, Eu, Gd and Dy): A study of the dependence of superconductivity on oxygen stoichiometry

Nagarajan, R and Vijayaraghavan, R and Ganapathi, L and Ram, Mohan RA and Rao, CNR (1989) Evidence for two distinct orthorhombic structures associated with different Tc regimes in LnBa2Cu3O7 − δ (Ln = Nd, Eu, Gd and Dy): A study of the dependence of superconductivity on oxygen stoichiometry. In: Physica C: Superconductivity, 158 (3). pp. 453-457.

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Abstract

Superconductivity in LnBa2Cu3O7 − δ with Ln = Nd, Eu, Gdand Dy has been investigated as a function of δ, closely following the accompanying changes in crystal structure. Orthorhombic GdBa2Cu3O7 − δ and DyBa2Cu3O7 − δ show a Tc of ≈ 90 K up to δ = 0.2 and a lower Tc plateau (40–50 K) in the δ range 02 to 0.4, similar to that found in YBa2Cu3O7 − δ. The orthorhombic structure II in the lower Tc regions is different from the structure I in the 90 K Tc (low δ) region. The unit cell parameters of the orthorhombic I structure in the high Tc region bear the relationship of a a ≠ b not, vert, similar c/3. This relationship is not seen in the low Tc plateau. The low Tc plateau region does not distinctly manifest itself in NdBa2Cu3O7 − δ just as in LaBa2Cu3O7 − δ.

Item Type:	Journal Article
Publication:	Physica C: Superconductivity
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	25 Aug 2010 05:33
Last Modified:	19 Sep 2010 06:14
URI:	http://eprints.iisc.ac.in/id/eprint/31370

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