Abstract
It has been reported by D. Paquette et al. that 55Mn nuclear spin-lattice relaxation (NSLR) rates in MnF2 exhibit criticallike divergent behaviour as the external field approaches HSF, the spin-flop field. The theoretical estimation for this phenomenon has been made by using the formalism of the nuclear magnon introduced by Ninio and Keffer. Quantitative agreement between experiment and theory is obtained.