Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 22: CE: Low-dimensional Systems - Materials 2

TT 22.9: Talk

Tuesday, March 15, 2011, 12:45–13:00, HSZ 304

Implications of Choosing the Local Coordinate Frame for the Understanding of Magnetism in Highly Anisotropic Co^II Clusters — •Joscha Nehrkorn¹, Sven Pfirrmann², Yanhua Lan², Annie K. Powell², and Oliver Waldmann¹ — ¹Physikalisches Institut, Universität Freiburg, Germany — ²Institut für anorganische Chemie, Universität Karlsruhe, KIT, Germany

Molecular nanomagnets containing Co^II ions are currently of much interest, because they provide large magnetic anisotropy and hence potentially superior magnetic properties. However, only relatively few examples can be found in the literature, which might be due to the complications in describing the magnetic properties of such clusters.

Here we report our studies of the magnetic properties in a polynuclear Co₂^IIICo₆^II complex. An effective low-temperature model reproduces excellently our magnetic data at the lowest temperatures and the general trend at higher temperatures. However, the derived exchange parameters are maximally anisotropic, while the energy spectrum is typical for the strong exchange limit, in which anisotropy is weak. This will be explained by noting the implications of the freedom to choose the local coordinate frame at will. The consequences thereof, which are potentially of general interest, will be discussed.