Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/242797
Type: Artigo
Title: Structural study of Ni-substituted YBaCo4-xNixO7 frustrated cobaltites
Author: Torre, L. M.
Aurelio, G.
Granado, E.
Sánchez, R. D.
Abstract: In this work we report a study of the thermal stability and the evolution of the crystal structure of Ni-substituted YBaCo4-xNixO7 cobaltites, for x=0, 0.10 and 0.20. Synchrotron X-ray powder diffraction and thermodiffraction experiments show that the structural transition P31c -> Pbn2(1), which occurs around room temperature for the parent compound, is shifted up to 40 by the partial substitution Ni-for-Co. Moreover, the transition is shown to be of first order with a volume collapse of approximate to 0.05% and an abrupt contraction of the cell along the c-direction. The monoclinic distortion below 100 K reported for the parent compound is also observed in the Ni-substituted samples, suggesting that they also get to order antiferromagnetically below that temperature. Magnetization measurements allowed us to detect a small amount of a ferromagnetic impurity in the sample with x=0.20, indicating that the solubility limit of Ni lies below that value. The magnetic susceptibility in the paramagnetic region, as well as the cell parameters in each crystallographic phase, is not significantly modified by these amounts of Ni substitution, in contrast to the marked enhancement of the P31c phase stability upon substitution. (C) 2015 Elsevier Inc. All rights reserved.
In this work we report a study of the thermal stability and the evolution of the crystal structure of Ni-substituted YBaCo4-xNixO7 cobaltites, for x=0, 0.10 and 0.20. Synchrotron X-ray powder diffraction and thermodiffraction experiments show that the structural transition P31c -> Pbn2(1), which occurs around room temperature for the parent compound, is shifted up to 40 by the partial substitution Ni-for-Co. Moreover, the transition is shown to be of first order with a volume collapse of approximate to 0.05% and an abrupt contraction of the cell along the c-direction. The monoclinic distortion below 100 K reported for the parent compound is also observed in the Ni-substituted samples, suggesting that they also get to order antiferromagnetically below that temperature. Magnetization measurements allowed us to detect a small amount of a ferromagnetic impurity in the sample with x=0.20, indicating that the solubility limit of Ni lies below that value. The magnetic susceptibility in the paramagnetic region, as well as the cell parameters in each crystallographic phase, is not significantly modified by these amounts of Ni substitution, in contrast to the marked enhancement of the P31c phase stability upon substitution.
Subject: Cobaltitas, Raios - Difração, Frustração magnética
Country: Estados Unidos
Editor: Academic Press
Citation: Structural Study Of Ni-substituted Ybaco4-xnixo7 Frustrated Cobaltites. Academic Press Inc Elsevier Science, v. 230, p. 34-41 OCT-2015.
Rights: fechado
Identifier DOI: 10.1016/j.jssc.2015.06.030
Address: https://www.sciencedirect.com/science/article/pii/S0022459615300372
Date Issue: 2015
Appears in Collections:IFGW - Artigos e Outros Documentos

Files in This Item:
File SizeFormat 
000360516600006.pdf4.68 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.