Size effects on exchange bias in polycrystalline Ni–Fe/Fe–Mn square dots

The effects of the dot size on the exchange bias in the Ni-Fe/Fe-Mn square dots have been investigated. The exchange bias field and the blocking temperature of the square dots decrease as the dot size decreases. We consider this behavior is because the spins are fluctuated by the thermal activation in the laterally constricted antiferromagnetic grains which are located at the edges of the dots. (c) 2006 Elsevier B.V. All rights reserved.