Eur. Phys. J. B (2012) 85: 107
https://doi.org/10.1140/epjb/e2012-20835-6

Regular Article

Dipolar-controlled spin tunneling and relaxation in molecular magnets

Department of Physics and Astronomy, Lehman College, City University of New York, 250, Bedford Park Boulevard West, Bronx, 10468 New York, USA

^a e-mail: dmitry.garanin@lehman.cuny.edu

Received: 13 October 2011
Received in final form: 9 February 2012
Published online: 28 March 2012

Abstract

Spin tunneling in molecular magnets controlled by dipole-dipole interactions (DDI) in the disordered state has been considered numerically on the basis of the microscopic model using the quantum mean-field approximation. In the actual case of a strong DDI, coherence of spin tunneling is completely lost and there is a slow relaxation of magnetization, described by t^3/4 at short times. Fast precessing nuclear spins, included in the model microscopically, only moderately speed up the relaxation.