Eur. Phys. J. B 16, 423-427 (2000)
https://doi.org/10.1007/PL00011079

Double-Q magnetic structures and strong planar anisotropy in tetragonal ErRu₂Ge₂ and ErRu₂Si₂

¹ Laboratoire Louis Néel, CNRS, BP 166, 38042 Grenoble Cedex 9, France
² Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9, France
³ Faculty of Science, Yamaguchi University, Yamaguchi 753, Japan

Corresponding author: ^a gignoux@polycnrs-gre.fr

Received: 24 December 1999
Published online: 15 August 2000

Abstract

Single crystal magnetization measurements and powder neutron diffraction on tetragonal ErRu₂Ge₂ as well as anisotropy of the paramagnetic susceptibility and specific heat measurements on ErRu₂Si₂ are presented. Besides the huge crystal field contribution to the uniaxial anisotropy, which favors the basal plane, a strong in-plane anisotropy is evidenced. From these features and neutron diffraction experiments it is shown that magnetic structures of these materials are double-Q and accordingly non-colinear below their Néel temperature (5.2 and 6.0 K for Ge and Si based compounds, respectively). The magnetic structures induced during the metamagnetic processes are discussed.