@article{b95d58da7600437db14c5c8178d1a5c5,
title = "Calorimetric evidence of antiferromagnetism in GdBa2Cu3O6+δ",
abstract = "Heat capacity measurements between 1.8 and 10K have been made on the superconductor GdBa2Cu3O6+δ with δ \{reversed tilde equals\} 0.7 and Tc \{reversed tilde equals\} 94K. A well defined magnetic transition prevails at 2.22K. The entropy involved agrees well with the complete antiferromagnetic ordering of Gd3+ ions.",
author = "Ho, \{J. C.\} and Hor, \{P. H.\} and Meng, \{R. L.\} and Chu, \{C. W.\} and Huang, \{C. Y.\}",
note = "Funding Information: T. A well defined anomaly prevails with its peak at 2.22K. It is clear\textbackslash{}]\textasciitilde{}y associated with magnetic ordering of Gd \textasciitilde{}+ ions, because a similar experiment on YBa\textasciitilde{}Cu\textasciitilde{}O-j o 6 shows no trace of such an ef\textbackslash{}[ect. \textasciitilde{}rthermore, with one mole of Gd \textasciitilde{}+ in each mole of GdBa2CuqO6+ a , the entropy involved in the obse-rve\textasciitilde{}d br\textasciitilde{}dering as measured by the area under the curve is almost 100\% of R£n8 : 17.3 J/mol-K \textasciitilde{}s expected for a complete ordering of Gd \textasciitilde{}+ ions. Uncertainties due to the relatively small lattice and electronic contributions to the total b\textasciitilde{}at capacity In this temperature range, as well as the extrapolation\textasciitilde{}p\textasciitilde{}f data to absolute zero based on a T j/L dependence, are at most a few percent. In addition, we would like to point out that the N\textasciitilde{}el temperature of 2.22K is consistent with the Curle-Weiss temperature of \textasciitilde{} ---6K as shown in the inset in Fig. I, from susceptlbility measurements made in the normal state. In conclusion, we have observed a heat capacity anomaly in GdBa\textasciitilde{}Cu\textasciitilde{}O\_ 6+6 associated width antlferrom\textasciitilde{}agnetic ordering of Gd j+ ions at 2.22K, below which antiferromagnetism coexists with superconductivity. At present the mechanism leading to this magnetic ordering is not known. More experimental studies are needed in order to understand how antlferromagetism arises in this high temperature superconductor. We would llke to thank C.S. Ting for some stimulating discussions, and C.C. Ho for data analysis. The work at the University of Houston is supported by NSF Grant No. DMR 86-16539, NASA Grant Nos. NAGW-977 and NAG8-51, and the University of Houston; and that at Lockheed by the Lockheed Independent Research funds.",
year = "1987",
month = aug,
doi = "10.1016/0038-1098(87)90115-3",
language = "English",
volume = "63",
pages = "711--712",
journal = "Solid State Communications",
issn = "0038-1098",
publisher = "Elsevier Limited",
number = "8",
}