Regensburg 2004 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Magnetismus

MA 21: Bio- und molekularer Magnetismus

MA 21.8: Vortrag

Donnerstag, 11. März 2004, 12:00–12:15, H22

Magnetic Resonance Spectroscopic Studies of Magnetization Relaxation in Single-Crystalline Mn₁₂Ac — •Joris van Slageren¹, Suriyakan Vongtragool¹, Nadeschda Kirchner¹, Martin Dressel¹, Alexander Mukhin², and Boris Gorshunov² — ¹1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany — ²General Physics Institute, Russian Academy of Sciences, Moscow, Russia

New, spectroscopic experiments on the magnetization relaxation of the single molecule magnet Mn₁₂Ac are presented. These studies were performed using frequency domain magnetic resonance spectroscopy on single crystalline samples. Special attention is paid to the consequences of the known distribution of zero-field splitting parameters on the relaxation dynamics. It is also shown, that the resonance spectrum of the magnetized sample recorded in zero external field has a peculiar shape in Faraday geometry, due to a combination of the resonance phenomenon and the Faraday effect. The nonmagnetized sample shows a normal spectral shape. In this way it is possible to study magnetization relaxation in zero external field. Finally, we have succeeded in performing selective magnetodipolar excitations on one side of the potential energy double well, by using circularly polarized radiation. This offers another possibility for studying magnetization relaxation in zero external field, which is not possible when using linearly polarized radiation. These studies are important to investigate the role of accidental transverse magnetic field on the relaxation behaviour of single molecule magnets.