Experimente an der Neutronenquelle des Hahn-Meitner-Instituts, Berlin. Magnetic structure of ErCl3

• Research unit: EU RFP
• Project number: 96.0436-1

Key words (English)

Magnetic structure; powder neutron diffraction; erbium halides

Alternative project number (English)

EU project number: ERBFMGECT950060

Research programs (English)

EU-programme: 4. Frame Research Programme - 10.1 Stimulation of training and mobility

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
Universität Bern
Departement für Chemie und Biochemie

Abstract (English)

Competing interactions in low-dimensional magnetic systems often lead to unusual magnetic ordering and critical phenomena. The simple binary systems ErX3 (X=Cl,Br,I) constitute a family of insulating compounds with closely related layer structures in which the Er3+ ions form 2-D honey comb lattices. Unusual magnetic ordering phenomena have been observed in these compounds in the milli Kelvin temperature range. The ratio of interlayer to intralayer coupling and thus the critical behavior and the nature of the magnetic order can be tuned by chemical variation. In all three lattices the 2-D magnetic order within the layers is a new type of two-sublattice, 120° antiferromagnetic order with an infinite rotational degeneracy. The ordered magnetic moments are 3.3, 4.7 and 5.5 mB/Er3+ for ErCl3, ErBr3 and ErI3, respectively. ErCl3 shows a transition to 3-D magnetic order at 350 mK with a k-vector of (2/3 0 -1/12), ErBr3 and ErI3 show 2-D order with a 3-D correlation length of 15 Å below 280 mK, pure 2-D order up to 400 mK, and short range 2-D order up to several Kelvin. The differences are attributed to the different layer stackings in ErCl3 and ErBr3/ErI3 as well as the variation of interlayer distances.
The magnetic structures were determined from single crystal neutron measurements at the V1 diffractometer of the Hahn-Meitner Institut, Berlin, together with powder neutron measurements at the D1A and D1B diffractometers at the Institut Laue-Langevin, Grenoble.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 96.0436-1