| Popis: |
NMR measurements are reported here on a particular ${\mathrm{Ce}}^{3+}$-doped Ca${\mathrm{F}}_{2}$ crystal which, when analyzed in the light of existing relaxation theory, yield explicit expressions for the effective magnetic moment of the paramagnetic spin, its associated autocorrelation time, and the contribution of the surrounding shifted nuclei to the second moment of the nuclear-resonance line shape. Additional more direct measurements of this cross second moment using both Mansfield's coherent-double-pulse technique and a free-induction-decay decomposition agree with the moment predicted by the above analysis to within experimental error. Some common pitfalls in the interpretation and comparison with theory of such data are also pointed out. Finally, attention is called to serious inconsistencies between the autocorrelation times resulting from this analysis and impurity-spin-lattice relaxation times obtained from EPR measurements on similar systems. |
