Properties of microsamples of sintered cobalt--samarium magnets

Hysteresis loops of small but still multi-grain samples taken from sintered Co5Sm magnets show a wide range of behavior, samples from the same magnet bracketing the bulk properties. Magnetization discontinuities often appear and are associated with large grains. These jumps show a quantized dependence of jump field on magnetizing field and often a good l/costheta dependence, exactly as in particles prepared from cast material. A sample consisting of only one grain gave a completely rectangular loop. Measurements on sintered magnets indicated that large grains tend to reverse in small fields, detracting from the over-all properties