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