Exchange bias in thin Heusler alloy films in contact with antiferromagnet.

Exchange bias is studied in thin film systems, in which three types of Heusler alloys (Ni2MnSn, Co2MnSn, and Co2FeSi) are in contact with an antiferromagnet. Magnetic exchange interactions between the constituting atoms (i.e., Ni-Mn, Mn-Mn, Co-Mn, and Co-Fe, or Co-Co) differ substantially in these Heusler alloys. We explain the influence of the exchange stiffness A within the Heusler alloys and of the exchange coupling between Heusler alloy and an antiferromagnet in a finite interface volume. Insertion of an ultrathin Co layer at interfaces brings about an enhancement of the exchange bias in Heusler alloy/antiferromagnet layer system. [ABSTRACT FROM AUTHOR]