Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 33: Biomedical and molecular magnetism
MA 33.1: Vortrag
Mittwoch, 14. März 2018, 15:00–15:15, H 1012
Pictorial description of elementary excitations in ferromagnetic molecular magnets — •Krunoslav Prsa and Oliver Waldmann — Physikalisches Institut, Universität Freiburg, Germany
The common spin-wave approximation of many-body effects in magnetic solids can be used to describe excitations from the ferromagnetic (S=Smax) ground state in molecular magnets. Starting from the Heisenberg Hamiltonian, both the classical and the quantum approaches provide exact solutions of the transitions from the ground state into the M=Mmax−1 sector, which are observed in neutron scattering experiments at low temperatures. With the help of the classical approach we infer pictorial descriptions of the magnon wavefunctions similar to the illustrations of the vibrational normal modes in molecules. The magnetic normal modes correspond to a set of standing waves of precession around the polarized ground state. We argue that this representation leads to a better intuitive understanding of the excitations, their symmetry properties, and has links to the energy and wavevector dependence of intensity in the neutron scattering experiments.