Magnetization and spin dynamics of a Cr-based magnetic cluster: Cr${}_7$Ni

Abstract

We study the magnetization and the spin dynamics of the Cr${}_7$Ni ring-shaped magnetic cluster. Measurements of the magnetization at high pulsed fields and low temperature are compared to calculations and show that the spin Hamiltonian approach provides a good description of Cr${}_7$Ni magnetic molecule. In addition, the phonon-induced relaxation dynamics of molecular observables has been investigated. By assuming the spin-phonon coupling to take place through the modulation of the local crystal fields, it is possible to evaluate the decay of fluctuations of two generic molecular observables. The nuclear spin-lattice relaxation rate $1/T_1$ directly probes such fluctuations, and allows to determine the magnetoelastic coupling strength.

3 pages, 2 figures, submitted as a contributed article for the Jems conference in Dublin (September 14-19 2008)