Hyperfine field distributions in disordered Mn2CoSn and Mn2NiSn Heusler alloys

Heusler alloys, Mn2CoSn and Mn2NiSn, were prepared and characterized by X-ray studies. Mossbauer studies using Sn-119 were carried out to investigate the hyperfine fields present at the So site in these alloys. The hyperfine field distribution in these alloys as well as X-ray studies point to the chemical disorder present in both alloys. Co-existence of a paramagnetic portion along with the magnetic hyperfine part was observed in Mn2CoSn even at low temperatures, while this was not found in Mn2NiSn spectra. Hyperfine fields at Sn site were calculated using Blandin and Campbell model and compared with the experimental results.