Antiferromagnetic phase transition in ordered FePt3 investigated by angle-resolved photoemission spectroscopy

The electronic band structure of ordered FePt3 (110) single crystal was studied by angle-resolved photoemission spectroscopy with synchrotron radiation. The energy band dispersions along the X-Γ-X and R-M-R directions of a simple cubic Brillouin zone were successfully observed at room temperature. Along the latter direction, band folding due to antiferromagnetic (AF) ordering was clearly observed below the Neel temperature (TN2) of 100 K. Through comparison with theoretical calculations, (1/2, 0, 0)-type AF ordering or a mixture of the (1/2, 0, 0)-type and (1/2, 1/2, 0)-type AF orderings was concluded to occur below TN2. These magnetic orderings can be understood from the viewpoint of the nesting between the electron and hole pockets. (author)