CANCELLED !!! Talk on "Dielectric and magnetic behavior of pure and doped clusters"

16.02.2018 14:00 - 15:30

by Rolf Schäfer; Eduard-Zintl-Institut für Anorganische und Physikalische Chemie

Technische Universität Darmstadt

Magnetic (Stern-Gerlach) and electric (Stark) beam deflection experiments combined with density functional theory allows to systematically study the influence of the molecular structure on the magnetic response of magnetic nanoalloy clusters.

The clusters are produced in a pulsed laser vaporization source using a temperature controlled nozzle to investigate the influence of thermally activated molecular degrees of freedom, especially on the magnetic response. The dielectric properties of the clusters are investigated in order to identify the molecular structure of the clusters. In the high temperature regime all clusters exclusively show high magnetic field seeking response and magnetic dipole moments are extracted from the shifts of the molecular beams. At low nozzle temperatures some of the cluster display considerably broadened beam profiles due to a non-uniform deflection in the magnetic field. The results reflect the influence of the chemical environment of the transition metals on magnetic properties in atomic domain magnetic nanoalloys. The different ground state spin multiplicities and coupling of rotational and vibrational degrees of freedom to the spin angular momenta in isolated clusters of different size apparently cause these variations of spin orientation. This is discussed qualitatively by taking electronic and molecular structure data into account obtained from density functional theory calculations of globally optimized host structures encapsulating a transition metal atom. Since some of the clusters show an atomic behavior at low nozzle temperatures, i.e. the projection of the spin angular momentum along the field direction is a constant of motion, double Stern-Gerlach experiments have been performed in order to study the refocusing properties of the investigated clusters. This paves the way to perform magnetic resonance experiments on endohedrally doped metal clusters in the future.

Host: Markus Arndt
Josef-Stefan-HS, 3rd floor Boltzmanngasse 5, 1090 Vienna