Séminaire du mercredi 15 décembre 2010 à 11h

Séminaire de Vladimir Dmitrienko

en salle 410 (4e étage) couloir 23-24

Dzyaloshinskii?Moriya Interaction: How to Measure Its Sign in Weak Ferromagnets?

Résumé :
Three experimental techniques sensitive to the sign of the Dzyaloshinskii?Moriya
interaction are discussed: neutron diffraction, Mössbauer gamma-ray diffraction,
and resonant x-ray scattering. Classical examples of hematite (Fe₂O₃) and
MnCO₃ crystals are considered in detail.


V. E. Dmitrienko (a),

E. N. Ovchinnikova (b)

J. Kokubun (c)

K. Ishida (c)


a Shubnikov Institute of Crystallography, Moscow, 119333 Russia
b Faculty of Physics, Moscow State University, Moscow, 119899 Russia
c Faculty of Science and Technology, Tokyo University of Science, Noda, 278_8510 Chiba, Japan

En savoir plus

The Dzyaloshinskii?Moriya relativistic interaction between spins is considered for more than fifty years as a mechanism of week ferromagnetism in antiferromagnetic crystals. It induces small canting of opposite magnetic moments, hence a small ferromagnetic moment. For macroscopic phenomenological description of non-chiral crystals the sign of the Dzyaloshinskii?Moriya interaction is not important. Only recently some ab initio methods have been developed for calculation of value and sign of this interaction. In this report we will discuss how to measure this sign experimentally. Three possible techniques sensitive to the sign of the Dzyaloshinskii?Moriya interaction are discussed: neutron diffraction, Mössbauer ?-ray diffraction, and (mainly) resonant x-ray scattering. Classical examples of hematite (?-Fe2O3) and MnCO3 crystals are considered in detail.