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Tunnel window's imprint on dipolar field distributions
1Departamento de Física Aplicada I, Universidad de Málaga, 29071-Málaga, Spain.
Physical Review Letters
|September 5, 2001
Summary
Monte Carlo simulations reveal quantum tunneling in magnetic clusters. The study found a relationship between the hole width in dipolar field distributions and energy changes during spin flips at low temperatures.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Computational Physics
Background:
- Studying quantum tunneling in magnetic clusters is crucial for understanding low-temperature magnetic phenomena.
- Experiments on systems like Fe(8) provide insights into spin dynamics.
Purpose of the Study:
- To simulate interacting dipoles relaxing via quantum tunneling.
- To mimic experimental conditions of magnetic cluster crystals at very low temperatures.
- To investigate the time evolution of the dipolar field distribution.
Main Methods:
- Monte Carlo simulations were employed.
- Simulations incorporated quantum tunneling for spin flips.
- Energy changes for spin flips were constrained by a threshold (2 delta hf).
Main Results:
- A "hole" phenomenon was observed in the dipolar field distribution over time, mirroring experimental findings.
- The half-width (W) of these incipient holes in weakly polarized systems was found to be related to delta hf.
- Under specific conditions (kBT < 0.5 delta hf and delta hf < 1/10 of disordered system width), W was approximately 0.75 delta hf.
Conclusions:
- The simulations successfully replicate key experimental observations in magnetic cluster tunneling.
- A quantitative relationship between hole width and tunneling energy threshold was established.
- The findings contribute to the understanding of quantum tunneling dynamics in magnetic systems.