Macroscopic quantum tunnelling and hysteresis loops of mesoscopic magnets
Moscow State University, Physics Department, Vorobievy gory, Moscow 119899, Russia
2 Institute of General Physics of RAS - Vavilova st., 38, Moscow 117942, Russia
Accepted: 1 April 1997
Theoretical investigation of the magnetisation process in high-spin cluster is performed. The source of hysteresis is studied; magnetisation jumps on hysteresis loops of a cluster corresponding to intersections of energy levels are described theoretically. An analytical formula for the dependence of the height of a jump on the sweeping rate of external field is obtained. It is shown that the width of a jump is crucially influenced by fluctuating fields produced by the cluster environment.
PACS: 75.45.+j – Macroscopic quantum phenomena in magnetic systems / 75.60.Ej – Magnetisation curves, hysteresis, Barkhausen and related effects / 75.20.Ck – Nonmetals
© EDP Sciences, 1997