https://doi.org/10.1007/s100510070075
Triangular antiferromagnetic order in the honeycomb layer lattice of ErCl3
1
Department for Chemistry and Biochemistry, University of Bern,
Freiestrasse 3, 3000 Bern 9, Switzerland
2
Laboratory for Neutron Scattering, Paul Scherrer Institute and ETH Zürich,
5232 Villigen PSI, Switzerland
3
Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9, France
4
Hahn-Meitner Institute, Glienicker Strasse 100, 14109 Berlin, Germany
Received:
1
December
1999
Revised:
21
July
2000
Published online: 15 November 2000
ErCl3 crystallizes in the AlCl3-type layer structure. The crystal structure was refined in the
paramagnetic state by powder neutron diffraction. The monoclinic lattice parameters at 1.5 K
are a = 6.8040(3) Å, b = 11.7456(5) Å, c = 6.3187(3) Å and . The space group is
C2/m. Short-range, predominantly in-plane, magnetic ordering occurs above 350 mK up to
several Kelvin. Below
mK a three-dimensional antiferromagnetic order with a
propagation vector of
sets in. The magnetic structure of ErCl3 was determined
by powder and single-crystal neutron diffraction at temperatures down to 45 mK. The Er3+ ions
are located on two-dimensional honeycomb layers in the a-b plane. There are two
antiferromagnetically coupled
triangular sublattices which form right- and left-handed
helices along the c-axis. The magnetic moments are oriented in the a-b plane and amount to
3.3(1)
at saturation. From the temperature dependence of the integrated neutron
magnetic peak intensity a critical exponent
(2) was derived for the magnetic phase
transition.
PACS: 75.25.+z – Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.) / 75.40.-s – Critical-point effects, specific heats, short-range order / 61.12.Ld – Single-crystal and powder diffraction
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000