Christopher Dobe

Néel-vector tunneling in antiferromagnetic molecular clusters.

From inelastic neutron scattering experiments, we demonstrate quantum tunneling of the Neel vector in the antiferromagnetic molecular ferric wheel CsFe8. Analysis of the linewidth of the tunneling transition evidences coherent tunneling.

Quantized antiferromagnetic spin waves in the molecular Heisenberg ring CsFe8

We report on inelastic neutron-scattering (INS) measurements on the molecular spin ring

Electronic Raman transitions from the vanadium(III) hexa-aqua cation, in guanidinium vanadium sulphate

{\text{CsFe}}_{8}

Magnetic relaxation studies on a single-molecule magnet by time-resolved inelastic neutron scattering

, 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 molecules symmetry, only two parameters

Quantum dynamics of the Néel vector in the antiferromagnetic molecular wheel CsFe8

J

Variable temperature inelastic neutron scattering study of chromium(II) Tutton salt: manifestation of the 5E⊗e Jahn–Teller effect

and

High-Frequency Electron-Spin-Resonance Study of the Octanuclear Ferric Wheel CsFe8

D

Field-induced magnetoelastic instabilities in antiferromagnetic molecular wheels.

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.

Single-Molecule Magnets Under Pressure

Abstract Electronic Raman transitions ( 3 A → 3 E ( C 3 ) ) have been observed between the trigonally split components of the 3 T 1 g ( O h ) ground term of the vanadium(III) hexa-aqua cation in guanidinium vanadium sulphate hexa-hydrate. The magnitude of the trigonal field splitting is considerable, ∼2720 cm −1 , which is consistent with expectations based on the stereochemistry of the [V(OH 2 ) 6 ] 3+ complex. It is shown that a satisfactory reproduction of the electronic Raman band profile can be obtained only by assuming a ( 3 A ⊕ 3 E )⊗e vibronic coupling model.

A Family of Ferro- and Antiferromagnetically Coupled Decametallic Chromium(III) Wheels

Time-resolved inelastic neutron scattering measurements on an array of single-crystals of the single-molecule magnet Mn12ac are presented. The data facilitate a spectroscopic investigation of the slow relaxation of the magnetization in this compound in the time domain.