"Wigner crystal" and "stripe" models for the magnetic and crystallographic superstructures of La0.333Ca0 .667MnO3

Physics – Condensed Matter – Strongly Correlated Electrons

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

22 pages, 9 figures, submitted to Physical Review B

Scientific paper

10.1103/PhysRevB.59.14440

The crystallographic (charge-ordered) and magnetic superstructures of La0.333Ca0.667MnO3 were studied by high-resolution synchrotron x-ray and neutron powder diffraction. In the antiferromagnetic structure, which was refined using a non-collinear model, the a lattice parameter is tripled and the c lattice parameter is doubled with respect to the average crystallographic unit cell (Pnma setting). The crystallographic structure below the charge-ordering temperature (TCO ~ 260 K) is characterized by ordering of the dz2 orbitals of the Jahn-Teller-distorted Mn3+O6 octahedra in the orthorhombic ac plane, and the appearance of superlattice peaks in the x-ray patterns corresponding to a tripling of the a axis lattice parameter. The intensities of the superlattice peaks can be accounted for satisfactorily in terms of ordering of the Mn3+ cations in sites as far apart as possible in the ac plane ("Wigner crystal" model) and transverse displacements of the Mn4+O6 octahedra in the c direction. These results are not consistent with a recently proposed model based on transmission electron microscopy (TEM) data in which the Mn3+O6 octahedra are arranged in a stripe pattern ("stripe" model). In particular, the large longitudinal stripe modulation revealed by TEM is not observed, suggesting that the TEM data may not be representative of the bulk sample. Within the framework of the "Wigner crystal" model, the magnetic structure at 1.5 K and the charge-ordered superstructure at 160 K and 1.5 K were refined from the neutron data.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

"Wigner crystal" and "stripe" models for the magnetic and crystallographic superstructures of La0.333Ca0 .667MnO3 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with "Wigner crystal" and "stripe" models for the magnetic and crystallographic superstructures of La0.333Ca0 .667MnO3, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and "Wigner crystal" and "stripe" models for the magnetic and crystallographic superstructures of La0.333Ca0 .667MnO3 will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-17004

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.