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

The influence of antisite disorder occupancies on the magnetic properties of the half-metallic Co$_2$MnSi compound was studied by experimental techniques and first-principles calculations. The neutron diffraction studies show almost identical 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. Transport property measurement under magnetic field up to 9 Tesla revealed a positive magnetoresistance for bulk Co$_2$MnSi that persists up to room temperature. A Curie temperature of $\sim$1014 K was determined for the compound by high temperature electrical resistivity and dilatometry measurements.