https://doi.org/10.1007/s100510050996
Spin-spin correlations in the insulating and metallic phases of the Mott system V2O3
1
Department of Physics, Loughborough University, Leicester LE11 3TU, UK
2
Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9, France
3
Institut für Theoretische Physik, RWTH Aachen, Templergraben 55,
52056 Aachen, Germany
4
Max-Planck-Institut für Festkörperforschung, Heisenberg Straße 1,
70506 Stuttgart, Germany
Corresponding author: a K.R.Ziebeck@lboro.ac.uk
Received:
7
April
1999
Published online: 15 November 1999
The magnetic response in has been investigated using polarised
neutron scattering with polarisation analysis. Measurements were carried out
at three temperatures corresponding to the antiferromagnetic insulating
ground state, the metallic phase and the high temperature metallic phase. At
the first order metal insulator transition there is a dramatic change in the
magnetic response with the metallic and high temperature metallic phases
being characterised by ferromagnetic spatial correlations of the paramagnetic
response. The establishment of ferromagnetic correlations at the metal
insulator transition accounts for the abrupt jump in the uniform susceptibility.
It is proposed that the differentiation of the V-V distances across the edges of
octahedra is of critical importance for the change in electronic
conductivity but also for the establishment of the spatial correlations. The
gradual high temperature evolution of the conductivity then occurs by the
reduction in the vanadium d overlap brought about by thermal expansion.
The first order reduction in atomic volume which occurs on the establishment
of the metallic phase results from an instability of the vanadium local moment
arising from the change in electronic structure.
PACS: 71.30.+h – Metal insulator transitions and other electronic transitions / 75.25.+z – Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source X-ray scattering, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999