Calorimetric studies of the A1 to L1 0 transformation in FePt and related ternary alloy thin films J. Appl. Phys. 95, 7486 (2004); 10.1063/1.1682786Magnetocrystalline anisotropy and compositional order in Fe 0.5 Pt 0.5 : Calculations from an ab initio electronic modelIn structurally ordered magnetic thin films, the Curie temperature (T C ) of ferromagnetic films depends on the exchange integral of the short range ordered neighboring atoms. The exchange integral may be adjusted by controlling the elemental substitutional concentration at the lattice site of interest. We show how to control the T C in high anisotropy L1 0 Fe 50 Pt 50 magnetic thin films by substituting Rh into the Pt site. Rh substitution in L1 0 FePt modified the local atomic environment and the corresponding electronic properties, while retaining the ordered L1 0 phase. The analysis of extended x-ray Absorption Fine Structure spectra shows that Rh uniformly substitutes for Pt in L1 0 FePt. A model of antiferromagnetic defects caused by controlled Rh substitution of the Pt site, reducing the T C, is proposed to interpret this phenomenon and its validity is further examined by ab initio density functional calculations. V C 2014 AIP Publishing LLC.