Europhys. Lett.
Volume 48, Number 4, November 1999
Page(s) 410 - 414
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 September 2002
DOI: 10.1209/epl/i1999-00498-4

Europhys. Lett, 48 (4), pp. 410-414 (1999)

Structural change in $\rm DyCu_2$ single crystal induced by magnetic field

P. Svoboda 1, M. Doerr 2, M. Loewenhaupt 2, M. Rotter 2, T. Reif 3
F. Bourdarot 4 and P. Burlet 4

1 Department of Electronic Structures, Charles University
Ke Karlovu 5, 12116 Praha 2, Czech Republic
2 Institut für Angewandte Physik (IAPD) - TU Dresden, 01062 Dresden, Germany
3 Institut für Festkörperforschung, Forschungszentrum Jülich - 52425 Jülich, Germany
4 CEA, Département de Recherche Fondamentale sur la Matiére Condensée
SPSMS/MDN, 38054 Grenoble, France

(received 19 July 1999; accepted 15 September 1999)

PACS. 64.60$\rm -i$ - General studies of phase transitions.


The metamagnetic transition in the orthorhombic antiferromagnets $\rm RCu_2$ (R=Ce, Pr, Dy, Tb) in high magnetic fields parallel to the c-direction is connected with a conversion of the magnetic Ising axis from the orthorhombic a- to the c-direction. The new state remains stable even after switching off the field. A giant magnetostriction (GMS) $\Delta L/L \ge 1$ % is observed at the conversion. Neutron scattering experiments on a $\rm DyCu_2$ single crystal reveal that this axis conversion is also connected with a structural transition from the orthorhombic $\rm CeCu_2$-type structure to the hexagonal $\rm AlB_2$-type structure due to strong magnetoelastic coupling. To our knowledge this is the first observation of a change from low to high crystal lattice symmetry by application of an external magnetic field.


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