New Gd4-6-10 and Gd5-7-12 Cuprate Superconductors
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New Gd4‑6‑10 and Gd5‑7‑12 Cuprate Superconductors G. I. Supelano1 · D. Martinez Buitrago1 · J. A. Mejía Gómez2 · C. A. Parra Vargas1 · J. Albino Aguiar3 Received: 4 May 2020 / Accepted: 24 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract This paper describes the Gdx−2BaxCu2x−2Oδ (x = 6, 7) cuprate system synthesis using the conventional solid-state reaction method. Rietveld analysis of X-ray patterns evidences that samples crystallize in Pmm2 (#25) space group at room temperature with lattice parameter a = 3.8807 Å, b = 3.8735 Å, c = 38.7094 Å for Gd4Ba6Cu10Oδ and a = 3.8680 Å, b = 3.8763 Å, c = 46.5065 for Gd5Ba7Cu12Oδ. Resistivity measurements evidence zero-resistance state, which is a typical behavior of superconducting materials at bulk critical temperature of 15.5 K for Gd4Ba6Cu10Oδ and 22.1 K for Gd5Ba7Cu12Oδ. Keywords Gd4-6-10 · Gd5-7-12 · Superconductor · Resistivity properties
1 Introduction Since the discovery of superconductivity, numerous efforts have been made to find new compounds with higher transition temperature (TC). Within this search, the YBa2Cu3O7−δ (Y123) cuprate compound has gained popularity due to its TC > 90 K [1]. Y123 is composed of two CuO2 planes and one CuO chain [2]. The number of hole carriers in the oxygen sites in the CuO2 planes injected from CuO chain must be increased [2, 3] to increase TC in the YBCO family. Based on Y123, several Y124, Y247 and Y358 stoichiometry changes have been made resulting in a higher transition temperature of about 80, 40 and 100 K [4–6]. These compounds are characterized by their number of planes and chains. In general, improvement of TC in these superconductor systems depends on oxygen * G. I. Supelano [email protected] 1
Grupo Física de Materiales, Escuela de Física, Universidad Pedagógica y Tecnológica de Colombia, Tunja, Colombia
2
Universidad Antonio Nariño, Boyacá, Colombia
3
Laboratório de Supercondutividade e Materiais Avançados, Departamento de Física, Universidade Federal de Pernambuco, Recife, Pe 50970‑901, Brazil
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Vol.:(0123456789)
Journal of Low Temperature Physics
content, number of CuO chains and CuO2 planes [3, 6, 7]. Furthermore, substitution in Y, Ba and Cu sites has been reported to cause some effect in the superconducting properties [2, 8–10]. Udomsamuthirum et al. [3] reported the Y5-6-11, Y7-9-11, Y5-8-13, Y7-1118, Y156, Y3-8-11 and Y13-20-23 compounds and proposed the general formula Yx−2BaxCu2x−2Oδ to synthesize new superconductors. They established a relation between the number of C uO2 planes and the number of Ba atoms, together with the number of CuO chains and the number of Y atoms, as well as the number of Baatoms and Y-atoms, and the number of Cu-atoms. In comparison with Y123, Gd123 is a superconductor that exhibits similar structural and superconducting properties [11, 12]. Gd123 is orthorhombic with lattice parameters a = 3.861 Å, b = 3.913 Å and c = 11.761 Å with TC = 90 K [11–13]. Therefore, this paper aims to evaluate whether the p
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