Square root relaxation: two possible mechanisms

Abstract

Magnetic relaxation in large spin molecular paramagnets is often found to behave as the square root of time 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 the square root of t and finally to decay exponentially. This behaviour may be mostly expected in dilute systems.

References in corpus (2)

• Crossover between Thermally Assisted and Pure Quantum Tunneling in Molecular Magnet Mn12-Acetate
• Nuclear spin dynamics in the quantum regime of a single-molecule magnet

Cited by in corpus (4)

• Comparison among Various Expressions of Complex Admittance for Quantum System in Contact with Heat Reservoir
• Experimental Estimates of Dephasing Time in Molecular Magnets
• Dynamics and thermalization of the nuclear spin bath in the single-molecule magnet Mn12-ac: test for the theory of spin tunneling
• Low-Temperature Magnetization Relaxation in Magnetic Molecular Solids