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

Abstract

The inelastic neutron scattering (INS) spectrum is studied for the antiferromagnetic molecular wheel CsFe8, in the temperature range 2 - 60 K, and for transfer energies up 3.6 meV. A qualitative analysis shows that the observed peaks correspond to the transitions between the L-band states, from the ground state up to the S = 5 multiplet. For a quantitative analysis, the wheel is described by a microscopic spin Hamiltonian (SH), which includes the nearest-neighbor Heisenberg exchange interactions and uniaxial easy-axis single-ion anisotropy, characterized by the constants J and D, respectively. For a best-fit determination of J and D, the L band is modeled by an effective SH, and the effective SH concept extended such as to facilitate an accurate calculation of INS scattering intensities, overcoming difficulties with the dimension of the Hilbert space. The low-energy magnetism in CsFe8 is excellently described by the generic SH used. The two lowest states are characterized by a tunneling of the Neel vector, as found previously, while the higher-lying states are well described as rotational modes of the Neel vector.

arXiv comment12 pages, 10 figures, REVTEX4, to appear in PRB

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Cited by in corpus (13)

• Magnetic Cluster Excitations
• The even-odd effect in short antiferromagnetic Heisenberg chains
• Discrete antiferromagnetic spin-wave excitations in the giant ferric wheel Fe18
• Quantum Dynamics in the Thermodynamic Limit
• Quantized antiferromagnetic spin waves in the molecular Heisenberg ring CsFe${}_8$
• Direct observation of mixing of spin-multiplets in an antiferromagnetic molecular nanomagnet by electron paramagnetic resonance
• Exchange-coupling constants, spin density map, and Q dependence of the inelastic neutron scattering intensity in single-molecule magnets
• Field-induced level crossings in spin clusters: Thermodynamics and magneto-elastic instability
• Macroscopic quantum spin tunnelling with two interacting spins
• Huge Transverse Magnetization in the Field-Induced Phase of the Antiferromagnetic Molecular Wheel CsFe8
• Antiferromagnetic molecular nanomagnets with odd-numbered coupled spins
• Phase transition between quantum and classical regimes for the escape rate of dimeric molecular nanomagnets in a staggered magnetic field
• Quantum-classical phase transition of the escape rate of two-sublattice antiferromagnetic large spins