Regensburg 2013 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 40: Molecular Magnetism

MA 40.3: Vortrag

Donnerstag, 14. März 2013, 15:30–15:45, H23

Exchange-based and single-ion based relaxation of the magnetization in Ni₂Dy — •Alexander Sundt¹, Amin Khan², Pascal Wendler¹, Yanhua Lan², Annie K. Powell², and Oliver Waldmann¹ — ¹Physikalisches Institut, Universität Freiburg, Germany — ²Institute of Inorganic Chemistry, Karlsruhe Institute of Technologie, Germany

Ever since the discovery of slow relaxation of the magnetization at the molecular scale in Mn₁₂ac scientists focused on increasing the energy barrier for magnetization reversal U_eff in order to lift the single molecule magnet (SMM) behaviour from cryogenic to easier accessible temperatures for possible applications. A promising road to increase U_eff is the incorporation of highly anisotropic magnetic ions such as rare earth ions in heterometallic SMMs. However, using these ions presents novel challenges such as complicated relaxation pathways.

In this talk we present an experimental study by means of AC and DC susceptibility as well as single crystal magnetization measurements on the 3d4f heterometallic SMM Ni₂Dy. The data show that the blocking mechanism for magnetization reversal undergoes as function of temperature a crossover from an exchange-based to a single-ion based relaxation mechanism. In contrast to the situation in Co₂Dy₂, where we could identify the phenomenon for the first time [1], some significant differences are observed, which will be discussed.

[1] K. C. Mondal, A. Sundt, et. al., Angew. Chem. 124, 7668 (2012)