Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 2: Supraleitung: Mechanismen, Phasendiagramm, konkurrierende Ordnungen

TT 2.2: Vortrag

Montag, 8. März 2004, 11:45–12:00, H20

Local Fluctuating Charge Order in the Stripe Ground State of La_1.8−xEu_0.2Sr_xCuO₄ — •Hans-Joachim Grafe^1,2, Nicholas J. Curro², Markus Hücker³, and Bernd Büchner¹ — ¹Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, 01171 Dresden, Germany — ²Los Alamos National Laboratory, Los Alamos, NM 87545, USA — ³Brookhaven National Laboratory, Upton, NY 11973, USA

Nuclear Magnetic Resonance (NMR) studies of the planar oxygen sites in the cuprate superconductors provides information about both local spin and charge excitations. Here we report the striking observation of a strongly temperature dependent electric field gradient (EFG) at the planar oxygen site in antiferromagnetic stripe ordered La_1.8−xEu_0.2Sr_xCuO₄, which stands in stark contrast to the temperature independent result in superconducting La_2−xSr_xCuO₄materials. Furthermore, measurements of the spin lattice relaxation rate of the planar oxygen suggest the presence of glassy charge fluctuations. We interpret these results as the consequence of inhomogeneously fluctuating charge order associated with the onset of static stripes.