Magnetism of rapidly quenched rhombohedral Zr2Co11-based nanocomposites

The effect of quench rate and Zr content on nanostructure and magnetic properties of melt-spun Zr x Co 100− x ( x = 16–21) is investigated. High quench rate favours the formation of rhombohedral Zr 2 Co 11 , which is the hard phase. The coercivity increases with an increase in quench rate. Zr addition in limited amounts decreases the grain size of magnetic phases, which may promote the effective exchange coupling of soft magnetic phases. Therefore, coercivity and maximum energy product of Zr 2 Co 11 -based materials are significantly enhanced. The best magnetic properties, i H c = 3.0 kOe and (BH) max = 4.6 MG Oe, which are the highest reported values among Co–Zr binary alloys, are achieved for x = 18. The temperature coefficients of coercivity and remanence between 100 and 380 K are −0.05% K −1 , comparable to those of alnico magnet.