Partial magnetization reversal in a perpendicular exchange-biased [Pd∕Co]∕FeMn film through laser annealing

Abstract

Partial magnetization reversal on the perpendicular exchange-bias characteristics in the [Pd∕Co]×5∕FeMn bilayered and [Pd∕Co]×2∕Cu∕Co∕[Pd∕Co]×2∕FeMn spin valve thin films was investigated using laser. The hysteresis loops were measured using the extraordinary Hall effect and magneto-optical Kerr effect (MOKE). By increasing the output intensity of the laser, the exchange-bias fields in the [Pd∕Co]×5∕FeMn bilayered thin film were gradually changed from negative to positive. The distribution of partial magnetization reversal in the vicinity of the laser spot was measured by using MOKE. Although the magnetic moment of the pinned layer was gradually reversed by using laser annealing in the MOKE loops of the [Pd∕Co]×2∕Cu∕Co∕[Pd∕Co]×2∕FeMn spin valves’ structure, that of the free layer was not changed. When the pattern size was decreased to 5×5μm2, the direction of exchange biasing was fully reversed through laser annealing without distorting the hysteresis loop. All the patterned samples below 100×100μm2 have the same hysteresis loop, and the reversed loops were not distorted and reduced when laser annealing was used.