Spin Dynamics and Quantum Tunneling in Fe8 Nanomagnet and in AFM Rings by NMR
- Iowa State Univ., Ames, IA (United States)
In this thesis, our main interest has been to investigate the spin dynamics and quantum tunneling in single molecule magnets (SMMs), For this we have selected two different classes of SMMs: a ferrimagnetic total high spin S = 10 cluster Fe8 and antiferromagnetic (AFM) ring-type clusters. For Fe8, our efforts have been devoted to the investigation of the quantum tunneling of magnetization in the very low temperature region. The most remarkable experimental finding in Fe8 is that the nuclear spin-lattice relaxation rate (1/T{sub l}) at low temperatures takes place via strong collision mechanism, and thus it allows to measure directly the tunneling rate vs T and H for the first time. For AFM rings, we have shown that 1/T{sub l} probes the thermal fluctuations of the magnetization in the intermediate temperature range. We find that the fluctuations are dominated by a single characteristic frequency which has a power law T-dependence indicative of fluctuations due to electron-acoustic phonon interactions.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- W-7405-Eng-82
- OSTI ID:
- 837265
- Report Number(s):
- IS-T 2015; TRN: US0500976
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); Submitted to Iowa State Univ., Ames, IA (US); PBD: 19 Dec 2004
- Country of Publication:
- United States
- Language:
- English
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