Structural and magnetic properties of mechanically milled Y1−xPrxCo5 compounds [x = 0, 0.1, 0.3, 0.5]

Samples of composition Y1−xPrxCo5 (x = 0, 0.1, 0.3, 0.5) were arc melted in an argon atmosphere, mechanically milled for various times and heat treated at about 1073 K for short periods of time, in order to obtain nanocrystalline compounds. The X-ray diffraction patterns after the heat treatment indicated a single hexagonal 1:5 phase for each composition. The unit cell parameters varied with Pr content in the Y1−xPrxCo5 series. The crystallite size determined from transmission electron micrographs was about 13 nm. The intrinsic coercivity increased with Pr content; a maximum coercivity of 1.17 MA/m and an enhanced relative remanence magnetization to maximum magnetization ratio σr/σmax = 0.71 were achieved after heat treatment for the composition Y0.5Pr0.5Co5. The enhanced magnetic properties suggest strong intergranular exchange coupling in this composition, consistent with the very fine crystallite size.