Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique
TT 16.49: Poster
Samstag, 5. März 2005, 11:00–16:30, Poster TU C
High-Energy Scattering Study of Charge and Orbital Order of Pr0.7(Ca0.9Sr0.1)0.3MnO3 under pressure — •S. Kiele1, J. Geck1, M. von Zimmermann2, N. Wizent1, B. Büchner1, and M.M. Abd-Elmeguid3 — 1Institut für Festkörperforschung, IFW Dresden, Helmholtzstr. 20, D-01171 Dresden — 2Hamburger Synchrotronsstrahlungslabor am DESY, Notkestr. 85, D-22603 Hamburg — 3II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln
We present a high-energy scattering study of the superlattice reflections attributed to charge and orbital order in
Pr0.7(Ca0.9Sr0.1)0.3MnO3 under hydrostatic pressure. Pure Pr0.7Ca0.3MnO3 shows an
antiferromagnetic insulating ground state with a longe-range charge and orbital order. Utilizing pressure it can be driven
to a ferromagnetic metallic state, where the long-range charge order is destroyed. The Sr-substituted system can be
understood in a phase separation scenario. Due to the different cation sizes, the double-exchange at the Sr-substituted
sites changes, leading to the formation of ferromagnetic metallic non-charge ordered regions in the antiferromagnetic
insulating charge ordered background. Under external pressure we found a drastic decrease of the onset of the
charge/orbital ordering temperature and a thermal hysteresis of the order parameter.
The measurements have been done at the HASYLAB beamline BW5 with a three-crystal setting utilizing a new implementation of
a clamp-type piston-cylinder cell of a relatively small size and reduced wall thickness in a closed-cycle cryostat on a
four-circle diffractometer.