2006 Volume 47 Issue 1 Pages 2-10
The electrical resistivity ρ, magnetic susceptibility χ, electronic specific heat coefficient γe, the Néel temperature TN and the electronic structure and the magnetocrystalline anisotropy energy (MAE) have been investigated for L10-type MnPt alloy system. This alloy system exhibits the characteristic behaviors of pseudo-gap type antiferromagnets, presenting with the highest TN, the smallest values of ρ, χ and γe in the vicinity of the equiatomic composition. The values of ρ, χ and γe increase with deviating from the equiatomic composition.
From the linear muffin-tin orbital (LMTO) band calculations, the L10-type MnPt alloy system has a pseudo-gap in the electronic structure and the density of states (DOS) at the Fermi energy (EF) is lowest at the equiatomic composition in accord with the experimental results. Furthermore, the results of the LMTO band calculations including the spin–orbit interaction make it clear that the direction of the magnetic moment of Mn in the equiatomic composition is parallel to the c-axis, consistent with the reported spin structure determined by neutron diffractions. The magnetocrystalline anisotropy constant K is about 1.39×106 J m−3 which is larger in magnitude than that of L10-type MnNi equiatomic alloy, though the signs are different.