Large exchange bias field in the Ni-Mn-Sn Heusler alloys with high content of Mn

The exchange bias properties have been investigated in bulk Mn(50)Ni(40-x)Sn(10+x) (x=0, 0.5, and 1) Heusler alloys with high content of Mn, in which the largest exchange bias field is up to 910 Oe for Mn(50)Ni(40)Sn(10) alloy. In these alloys, the excess Mn atoms would occupy not only the Sn sites but also the Ni sites, and the moments of Mn on Sn or Ni sites are coupled antiferromagnetically to those on the regular Mn sites, respectively. The origin of this considerably large exchange bias field has been discussed. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3428782]