2010/01/20 by J. Dreiser, Jan Dreiser, O. Waldmann +13 · 30 citations
Chemistry · Materials Science · Mathematics · Physics and Astronomy · #Advanced NMR Techniques and Applications #Anisotropy #Antiferromagnetism #Atomic physics #Condensed matter physics #Dispersion relation #Excited state #Ferromagnetism #Hamiltonian (control theory) #Heisenberg model #Ion #Lanthanide and Transition Metal Complexes #Magnetism in coordination complexes #Mathematics #Physics #Quantum mechanics #Spin (aerodynamics) #Spin wave #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.81.024408
published in Physical Review B 81(2) (American Physical Society) · 10 pages, 9 figures, REVTEX 4
openalex publication_date 2010/01/20 · arxiv created 2010/01/21 · arxiv updated 2010/02/26 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report on inelastic neutron-scattering (INS) measurements on the molecular spin ring CsFe8, in which eight spin-5/2 Fe(III) ions are coupled by nearest-neighbor antiferromagnetic Heisenberg interaction. We have recorded INS data on a nondeuterated powder sample up to high energies at the time-of-flight spectrometers FOCUS at PSI and MARI at ISIS, which clearly show the excitation of spin waves in the ring. Due to the small number of spin sites, the spin-wave dispersion relation is not continuous but quantized. Furthermore, the system exhibits a gap between the ground state and the first excited state. We have modeled our data using exact diagonalization of a Heisenberg-exchange Hamiltonian together with a small single-ion anisotropy term. Due to the molecule's symmetry, only two parameters J and D are needed to obtain excellent agreement with the data. The results can be well described within the framework of the rotational-band model as well as antiferromagnetic spin-wave theories.