Abstract
The spin dynamics of a cluster of four iron(III) ions characterized by a total spin ground state S T=5 and Ising anisotropy have been investigated by the 1H nuclear magnetic resonance (NMR) linewidth and 1H NMR spin-lattice relaxation rate 1/T 1 as a function of the temperature (0.5-295 K) and external magnetic field (0.3-7.2 T). At very low T (0.5 K) the spectrum becomes very broad indicating freezing of the Fe 3+ moments in a superparamagnetic state. The temperature dependence of T 1 -1 and T 2 -1 shows strong field dependent enhancement below 50 K which must be related to the spin dynamics of the Fe 3+ moment freezing process, although no quantitative theory of this is currently available.
Original language | English (US) |
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Pages (from-to) | 7173-7175 |
Number of pages | 3 |
Journal | Journal of Applied Physics |
Volume | 91 |
Issue number | 10 I |
DOIs | |
State | Published - May 15 2002 |
ASJC Scopus subject areas
- Physics and Astronomy(all)