Berlin 2008 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 33: Symposium: High-Temperature Superconductivity

TT 33.7: Talk

Thursday, February 28, 2008, 16:35–16:50, H 0104

Charge order in La_1.8−xEu_0.2Sr_xCuO₄ studied by resonant soft X-ray diffraction — •J. Fink^1,2, E. Weschke³, E. Schierle³, J. Geck⁴, H. Hawthorn⁴, H. Widati⁴, H.-H. Hu⁵, H. Dürr¹, B. Büchner², and G. A. Sawatzky⁴ — ¹BESSY, Albert-Einstein-Strasse 15, 12489 Berlin — ²IFW Dresden — ³Hahn-Meitner-Institut Berlin — ⁴UBC Vancouver, Canada — ⁵II. Physikalisches Institut, Universität Köln

Stripe-like phases in hole-doped cuprates, in which antiferromagnetic domains are separated by periodically spaced domain walls to which the charge carriers are segregated, are caused by a complex interplay between lattice defects and charge and spin degrees of freedom. In La_1.8−xEu_0.2Sr_xCuO₄ a stripe-like phase replaces almost the entire superconducting phase because in this system stripes are stabilized by the existence of a low-temperature tetragonal phase in a large concentration range. In order to directly prove the existence of charge ordering in these compounds we have used resonant soft X-ray scattering at the O1s and Cu2p edges. Long-range charge order exists at low temperatures and x close to 1/8. At higher temperatures and for x = 0.15 the coherence length is reduced due to fluctuations and/or a reduced order.