52.7 kOe high coercivity in Sm(Co<inf>0.9</inf>Cu<inf>0.1</inf>)<inf>4.8</inf> melt-spun ribbons

Fine grained Cu substituted melt-spun Sm(Co0.9Cu0.1)4.8 ribbons prepared with a wheel speed of 50 m/s exhibit a high coercivity of 52.7 kOe. Detailed magnetic studies like I and II quadrant magnetization-demagnetization characteristics, minor-loop measurement with increasing field and recoil behaviour have been carried out in combination with TEM studies. Fine spots of size ∼3 nm having different crystallographic orientations within the grains have been observed, and the high coercivity of the sample is attributed to complex domain wall interactions with the fine grain (∼55 nm) microstructure containing nanoscale heterogeneities.