A HIGH-RESOLUTION NEUTRON STUDY OF Y2FE15CR2 AT 77 K INCLUDING MAGNETIC-PROPERTIES

The crystallographic and magnetic structures of Y2Fe15Cr2 at 77 K have been refined by Rietveld analysis of the high-resolution neutron powd er diffraction data. The analysis indicates that Y2Fe15Cr2 has Th2Ni17 -type structure (P6(3)/mmc). The Cr atoms occupy 12j, 6g and 4f sites with occupancies 0.12, 0.10 and 0.50 respectively, but Cr atoms are ab sent at 12k sites. The magnetic moments of all of the magnetic atoms l ie in the plane perpendicular to the sixfold axes and exhibit planar m agnetic anisotropy. The relations between the interesting abnormal mag netic properties and the structure are discussed.