Are superparamagnetic spins classical?
arXiv:0806.2892 · doi:10.1103/PhysRevB.78.144413
Abstract
Effective giant spins of magnetic nanoparticles are considered classically in the conventional theory of superparamagnetism based on the Landau-Lifshitz-Langevin equation. However, microscopic calculations for a large spin with uniaxial anisotropy, coupled to the lattice via the simplest generic mechanism, show that the results of the conventional theory are not reproduced in the limit S ->\infty. In particular, the prefactor Gamma_0 in the Arrhenius escape rate over the barrier Gamma =Gamma_0 exp[-Delta U/(k_B T)] has an anomalously large sensitivity to symmetry-breaking interactions such as transverse field
6 EPL pages, 3 figure captions
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Cited by in corpus (5)
- Relaxation of a classical spin coupled to a strongly correlated electron system
- Reduced thermal stability of antiferromagnetic nanostructures
- Inertia effects in the real-time dynamics of a quantum spin coupled to a Fermi sea
- Macrospin approximation and quantum effects in models for magnetization reversal
- Nonlinear ac stationary response and dynamic magnetic hysteresis of quantum uniaxial superparamagnets