MAGNETIZATION-REVERSAL PROCESSES IN AN ULTRATHIN CO/AU FILM

摘要: Magnetization-reversal processes in a ferromagnetic cobalt film structure (Au/Co/Au), with perpendicular anisotropy, were investigated by magneto-optical magnetometry and microscopy. In the considered ultrathin Co film, magnetization reversal between two Ising-spin equilibrium states is dominated domain-wall motion mechanism. We focused our studies on initiated from given demagnetized state. Starting magnetically saturated state generated under large field ${\mathrm{H}}_{\mathrm{S}}$, applied to this created through magnetic aftereffects ${\mathrm{H}}_{\mathrm{d}}$ antiparallel but smaller than ${\mathrm{H}}_{\mathrm{S}}$ during selected time. Direct (${\mathrm{R}}^{\mathrm{D}}$) indirect (${\mathrm{R}}^{\mathrm{I}}$) are then studied for application of parallel ${\mathrm{H}}_{\mathrm{d}}$, respectively. The dynamics much faster ${\mathrm{R}}^{\mathrm{I}}$ process since it quasihomogeneous 'Swiss cheese' domain small nonreversed regions. accommodation phenomenon studied, domain-shape memory effect evidenced. A theoretical analysis proposed, starting model patchy inhomogeneous media realistic distribution local coercivities. pertinent parameters calculations deduced experimental data using appropriate analytical expressions relaxation time velocity field. Computer simulations these reproduce well evolution pattern different curves both ${\mathrm{R}}^{\mathrm{D}}$ processes.