Proceedings of the International Conference on Magnetism

J. Phys. Colloques 49 (1988) C8-2119-C8-2124
DOI: 10.1051/jphyscol:19888951

ANTIFERROMAGNETIC ORDERING AND PHASE DIAGRAM OF YBa₂Cu₃O_6+x

J. Rossat-Mignod¹, P. Burlet¹, M. J. Jurgens^{1, 2}, C. Vettier³, L. P. Regnault¹, J. Y. Henry¹, C. Ayache¹, L. Forro¹, H. Noel⁴, M. Potel⁴, P. Gougeon⁴ et J. C. Levet<sup>4

1</sup>  Centre d'Etudes Nucléaires de Grenoble, Département de Recherche Fondamentale, 85 X, 38041 Grenoble Cedex, France
²  From Kamerlingh Onnes Laboratory, Leiden, The Netherlands.
³  Institut Laue Langevin, 156 X, 38042 Grenoble Cedex, France
⁴  Laboratoire Chimie Minerale B, Université de Rennes I, 35042 Rennes, France

Abstract
Neutron scattering experiments on single crystals have allowed an accurate determination of the magnetic phase diagram of YBa₂Cu₃O_6+x. With increasing oxygen content the antiferromagnetic ordering of YBa₂Cu₃O₆ and T_N remain unchanged up to x = 0.2. For x > 0.2 both T_N and the ordered moment of Cu²⁺ ions in the Cu(2) site decrease and vanish abruptly around x ≈ 0.40. The Cu⁺ ions in the Cu(1) site do not order for any oxygen content. For x = 0.30 a reentrant behaviour is observed. Preliminary inelastic neutron scattering experiments on a rather large single crystal (0.2cm³) with x ≈ 0.3 are reported.