Eur. Phys. J. B 48, 173-177 (2005)
https://doi.org/10.1140/epjb/e2005-00396-7

Square root relaxation: two possible mechanisms

Département de Recherche Fondamentale sur la Matière Condensée D.S.M., Commissariat à l'Énergie Atomique, 17 Avenue des Martyrs, 38054 Grenoble Cedex 9, France

Corresponding author: ^a jvillain@cea.fr

Received: 19 January 2005
Revised: 23 June 2005
Published online: 16 December 2005

Abstract

Magnetic relaxation in large spin molecular paramagnets is often found to behave as at short times t. This behaviour was explained by Prokofiev & Stamp as arising from dipole interactions between molecular spins. However, as observed by Miyashita & Saito, the same behaviour can arise from a different mechanism which, in the present work, is related to hyperfine interactions. The Miyashita-Saito scheme is found to be possible at short times if the nuclear longitudinal spin relaxation is very slow. In the case of moderately slow nuclear spin relaxation, the electronic magnetization variation is initially proportional to t, then to and finally to . This behaviour may be mostly expected in dilute systems.