Structure and magnetic properties of the intermetalliccompounds Gd3Fe29-xTax

Abstract

Novel ternary intermetallic compounds Gd3Fe29-xTax (x = 0.5 and 0.6) with the Nd3Fe29-xTix-type structure were synthesized with Ta as anew stabilizing element, and their crystal structures and magneticproperties were investigated by x-ray powder diffraction andmagnetic measurement. The lattice parameters are a = 10.5895, b = 8.5348, c = 9.6988 Å, and β = 96.940° for x = 0.5, and a = 10.5938, b = 8.5379, c = 9.7018 Å, and β = 96.943° for x = 0.6. Rietveld refinement of the crystalstructure reveals that Ta atoms occupy exclusively threecrystallographic positions (4g, 4i3, 4i4), each with onlyone neighbouring Gd atom. According to the refinement results, thechemical compositions of the compounds are Gd3Fe28.55Ta0.45 for x = 0.5, and Gd3Fe28.46Ta0.54 for x = 0.6. The compounds exhibit aplanar magnetocrystalline anisotropy perpendicular to the [102]direction. The Curie temperature Tc, saturation momentMs, and anisotropy field HA are 502 K, 39.1 µB /f.u., and 7.3 T for x = 0.5 and 508 K, 38.9 µB /f.u.,and 7.2 T for x = 0.6, respectively.