Dresden 2011 – scientific programme
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MA: Fachverband Magnetismus
MA 3: Bio- and Molecular Magnetism
MA 3.2: Talk
Monday, March 14, 2011, 11:15–11:30, HSZ 401
Geometrical Frustration in Molecular Spin Triangles with S=1/2, 5/2 — •Nicolas Yèche1, Andrei Zvyagin1,2, Daniel Plaul3, Dirk Schuch3, Winfried Plass3, Eric Kampert4, Til Dellmann1, Christopher Baines5, Gwendolyne Pascua5, Hans-Henning Klauß1, and Hubertus Luetkens5 — 1Institut für Festkörperphysik ,TU Dresden — 2Institute for Low Temperature Physics and Engineering of the NAS of Ukraine, Kharkov — 3Institut für Anorganische Chemie, Uni Jena — 4Hochfeldlabor Dresden, FZ Dresden-Rossendorf — 5Paul Scherrer Institute, Villingen, Switzerland
In the study of finite geometrically frustrated system, the simplest problems that can be considered are paradoxically some of the hardest ones to observe experimentally. Thanks to sophisticated organic ligands, independent triangles of Cu(II) (S=1/2) and Fe(III) (S=5/2) were synthesized. Investigations carried out with macroscopic (pulsed and static field magnetization) and local probe techniques (µSR and 57Fe mössbauer spectroscopy) show characteristic behavior of frustrated systems. Comparison of the magnetization data with theoretical calculations indicates that the antiferromagnetic coupling in the Cu system is greater than 45K: the complex shows a single magnetization plateau up to 60T at about 1/3 of the expected saturation. As for the Fe compound, several clear magnetization steps are observed in pulsed field, hinting for a coupling constant of about 10K. Slow dynamic spin fluctuations are observed in mössbauer spectra and in the µSR measurements down to millikelvin temperatures.