Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.52: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

High-field magnetization studies of the quasi-1D quantum spin systems (Y,Nd)₂BaNiO₅ and Li₂ZrCuO₄ — •Florian Kretzschmar¹, Rüdiger Klingeler¹, Natalia Tristan¹, Yulieth Arango¹, Stefan-Ludwig Drechsler¹, Elena Popova³, Olga Volkova³, Alexander Vasiliev³, Harison Rakoto², and Bernd Büchner¹ — ¹Leibniz-Institute for Solid State and Materials Research IFW Dresden, 01171 Dresden, Germany — ²Laboratoire National des Champs Magnétiques Pulsés, 31432 Toulouse, France — ³Low Temperature Physics Department, Moscow State University, 119991 Moscow, Russia

Quasi-one-dimensional quantum spin systems show fascinating ground states which low-energy excitations can often nicely investigated by high field magnetisation studies. Here, we report on static (up to 17T) and pulsed (up to 60T) magnetic field studies on the highly frustrated S=1/2 spin chains in Li₂ZrCuO₄ and on the interplay of S=1 chains and classical 4f-moments in (Y_1−xNd_x)₂BaNiO₅. For the latter system, a Haldane gap is observed even for x=1 where long antiferromagnetic order is realized. For x=1, we find two field induced metamagnetic transitions which field dependence qualitatively changes for smaller x. We discuss this change in terms of the distance between Nd ions vs. the correlation length along the Haldane chains. In Li₂ZrCuO₄, our measurements on oriented powders show an unusual anisotropy. In addition, the saturation field of ∼20T implies that the inter-chain coupling plays a crucial role in such highly frustrated systems.