Magnetic and structural properties of Co$_2$MnSi based Heusler compound

Abstract

The influence of antisite disorder occupancies on the magnetic properties of the halfmetallic Co 2 MnSi compound was studied by experimental techniques and first-principles calculations. The neutron diffraction studies show almost equal amount of Mn and Co disorders of 6.5% and 7.6%, which was found to be in good agreement with density functional theory (DFT) calculations of the stable Co 2 MnSi system with the corresponding disorders. DFT studies reveal that antiferromagnetic interactions introduced by Mn disorder lead to a reduction of the net magnetic moment. The results are discussed in conjunction with neutron diffraction and magnetization measurements. Magnetotransport measurements revealed a positive magnetoresistance for bulk Co 2 MnSi, which decreases as temperature increases. A Curie temperature of ∼1014 K was determined for the compound by high-temperature electrical resistivity and dilatometry measurements.