Deaging in Gd 2(MoO 4) 3 by cyclic motion of a single planar domain wall

Abstract

The motion of a single planar 180° domain wall was studied in single-crystalline gadolinium molybdate, Gd2 (Mo O4) 3. The switching current and the instantaneous wall positions were recorded using polarized light in an optical microscope and subsequent image processing. A pronounced deaging (wake-up) effect is observed represented by an increase of domain-wall shift during cyclic switching at constant voltage amplitude. The experimental data are compared to computer simulations taking into account the kinetic imprint effect under ac cycling. The latter is the change of the spatial distribution of the internal bias field during cycling. It is shown that deaging (wake-up) arises for aged (screened) initial states. After long enough cycling, the spatial distribution of the internal bias field becomes steady state and the wall motion becomes reproducible in all its details. The final distribution of the internal bias field does not depend on the initial state of the sample. The activation energies for deaging and aging are equal within the experimental uncertainty and thus very likely stem from the same micromechanism. © 2005 American Institute of Physics.