Anisotropy induced large exchange bias behavior in ball milled Ni–Co–Mn–Sb alloys

Abstract

We report the effect of decrease in the grain size on the structural, magnetic and exchange bias (EB) behavior in ball milled Ni50−xCoxMn38Sb12 (x=0 and 5) Heusler alloys. The existence of a wide range of grain sizes in the ball milled samples results in dramatic changes in the structural and magnetic properties. For x=0, a large EB field of 3.2 kOe is observed in the ball milled sample, compared to a value of 245 Oe of the bulk sample. This increase is attributed to the enhanced exchange coupling between the soft and hard magnetic particles.