Münster 1997 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 4: Symmetrie des Ordnungsparameters, Streifenkorrelationen in HTSL

TT 4.6: Vortrag

Montag, 17. März 1997, 16:30–16:45, F1

INVESTIGATION OF STRIPE ORDERING IN La_1.775Sr_0.225NiO₄ WITH HARD X-RAYS — •M. von Zimmermann², A. Vigliante¹, T. Frello³, J. Madsen³, N.H. Andersen³, J. Tranquada¹, J.R. Schneider², and D. Gibbs¹ — ¹Department of Physics, Bookhaven National Laboratory, Upton, New York 11973 — ²Hamburger Synchrotronstrhlungslabor HASYLAB at Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, D-22603 Hamburg — ³Department of Solid State Physics, RisøNational Laboratory, DK-4000 Roskilde, Denmark

Recent neutron studies [1] have shown that spin and charge ordering occurs in La_1.775Sr_0.225NiO₄ with incommensurate to the crystal lattice. In order to investigate the charge ordering with enhanced resolution, we have chosen hard x-rays with an energy of 100 keV. An absorption length of 0.08 cm implies that the bulk of the crystal is probed, like in the Neutron diffraction experiment. The largest correlation length of 46 Å along h, 74 Å along k and 14 Å along l were found at 50 K. The temperature dependence and the incommensurability is comparable with the results the neutron investigations. Below 50 K the correlation length starts to decrease and shows a hysteresis. Charge ordering peaks have also been found in the corresponding cuprate system La_1.48Nd_0.4Sr_0.12CuO₄ at beamline x22 at Brookhaven Nat. Lab. with a photon energy of 8 keV. These experiments provide support to the idea that spins and charges order in stripes.

[1] J.M. Tranquada et al. accepted by Phys. Rev. B (1996)