Effect of disorder on the magnetic properties of SmCo5

Mechanical milling of initially ordered ferromagnetic SmCo5 produces dramatic increases in coercivity after short (15 min to 1 h) milling times, accompanied by remanence ratios on the order of 0.7 and shifted hysteresis loops. X-ray diffraction shows that milling induces both chemical and structural disorder. The hysteresis-loop shift is continuous and nonlinear with temperature over the range 5-300 K. The high coercivities are attributed to the formation of a nanostructure consisting of crystalline SmCo5 regions separated by a disordered interphase. [S0163-1829(99)02001-9].