Münster 1999 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 3: Elektronische Eigenschaften von HTSL

TT 3.1: Hauptvortrag

Montag, 22. März 1999, 10:00–10:30, F3

A common phase diagram for antiferromagnetism in La_2−xSr_xCuO₄ and Y_1−xCa_xBa₂Cu₃O₆ as seen by muon spin rotation — •Ch. Niedermayer¹, Th. Blasius¹, Ch. Bernhard², A. Golnik², A. Moodenbaugh³, and J.I. Budnick⁴ — ¹Universität Konstanz, Fakultät für Physik, D-78434 Konstanz, Germany — ²Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany — ³Department of Applied Science, Brookhaven National Laboratory, Upton, NY 11977, USA — ⁴Department of Physics and Institute for Material Science, University of Connecticut, Storrs, CT 06269, USA

By zero field muon spin rotation we studied the antiferromagnetic correlations in the single layer system La_2−xSr_xCuO₄ and the bilayer compound Y_1−xCa_xBa₂Cu₃O₆. We observe a common phase diagram as a function of hole doping per plane with two distinct transitions of the magnetic ground state. The first transition marks the border between the 3D antiferromagnetic state and a disordered state with short ranged magnetic correlations. The second transition coincides with the onset of superconductivity and marks a distinct change in the magnetic correlations that coexist with superconductivity. The data are discussed on the basis of a microscopic phase segregation of the doped holes into hole-rich and hole-poor regions.