Magnetization reversal in exchange biased Co/CoO patterns

The influence of patterning on exchange bias has been investigated using arrays of micron-sized Co/CoO dots with different lateral confinement and length-to-width ratio. The patterned samples show higher coercive and exchange bias fields than a continuous Co/CoO bilayer. As in unpatterned film, magnetization reversal mechanisms on opposite sides of the hysteresis loops of the microstructured samples are different. However, with the increase of lateral confinement and shape anisotropy of the dots, the asymmetry in the magnetization reversal starts to differ from that observed in continuous Co/CoO films.