Nanometric architecture of SmCo5 related magnetic properties

SmCo5 samples, initially melted in a cold crucible, were melt-spun on a Cu-(Co,Be) wheel, leading to the formation of thin chemically homogenous flakes. Sample composition is within the single phase domain SmCo5+x, with -0.05 <x <0.21. Series of 2 g of flakes were ball milled for a short time with a planetary miller, for which vials and plate rotations (omega/Omega) can be set independently. The coherent domain size and the strain rate were estimated from X-ray line broadening. Magnetic measurements were carried out at room temperature using a superconducting quantum interference device. X-ray diffraction experiments showed a typical decrease in grain size and increase in distortion rate with respect to the milling energy (proportional to omega.Omega (2)). They also revealed that the grain shape is strongly dependent on the milling conditions (omega.Omega). The magnetic hystereris loop, the coercivity, the magnetisation and the remanence ratio of these powders are seen to be very sensitive to the nanostructure and the milling conditions applied.