Münster 1999 – scientific programme
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TT: Tiefe Temperaturen
TT 17: Theorie HTSL
TT 17.2: Talk
Thursday, March 25, 1999, 10:00–10:15, F2
Magnetische interplanare Kopplungseffekte in der Multigitterverbindung Y2Ba4Cu7O15 — •Enrico Arrigoni1, Gerd Hildebrand1, Jörg Schmalian2, and Werner Hanke1 — 1Institut für Theoretische Physik Universität Würzburg, D-97074 Würzburg — 2Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Str., Urbana 61801, IL, USA
A bilayer Hubbard model with inequivalent planes is used to investigate the interplane magnetic coupling of the multilattice compound Y2Ba4Cu7O15 as inferred from NMR and NQR experiments [1]. Evaluation of the spin response, effective interaction, intra- and interplane spin-spin relaxation times show that strong antiferromagnetic fluctuations are responsible for a magnetic coupling between the planes, which leads to a tendency of the fluctuation in the two planes to equalize [2]. This equalization effect grows whit increasing in-plane antiferromagnetic fluctuations, i. e., with decreasing temperature and decreasing doping, while it is completely absent when the in-layer correlation length becomes of the order of one lattice spacing. This result is in good qualitative agreement with the NMR and NQR data on Y2Ba4Cu7O15
[1] R. Stern, M. Mali, J. Roos, and D. Brinkmann, Phys. Rev. B 52, R15734 (1995)
[2] G. Hildebrand, E. Arrigoni, J. Schmalian, and W. Hanke, The European Physical Journal B in press