REMAGNETIZATION PROCESSES OF ULTRATHIN MAGNETIC-FILMS WITH ISLANDS STRUCTURE

Magnetization delay recently observed in ultrathin ferromagnetic films has been discussed using the Fatuzzo theory assuming homogeneous magn et. However, the islands structure of ultrathin films is observed for small sample thicknesses. The ''islands'' model of magnet structure is proposed in the present work for the delay description. It is assumed that the sample is broken at magnetic clusters created by magnetic is lands connected by magnetic ''bridges'' and remagnetization of each cl uster undergoes independently. Function describing sample remagnetizat ion is obtained as a sum PSI(t)=pPSI(infinity)(t)+(1-p)[PSI(t)], where p is the concentration of infinite clusters; PSI(infinity)(t) is the function from the Fatuzzo theory, and [PSI(t)] is the remagnetization function averaged for a different number of islands in finite clusters . The presented model could be used for analysis of magnetization proc esses in other magnets consisting of magnetically interacting ''island s.''