Structure and magnetic properties of nanocrystalline Co-Ni and Co-Fe mechanically alloyed

Abstract Our previous studies relating to the effect of ball milling (BM) parameters on the microstructure and, consequently, on the magnetic properties have shown that the combination of low values of the plateau rotation Ω  and the high vial velocities ω can enhance the cubic phase formation and consequently the coercivity. However, the most relevant parameter remained the ball milling time. Indeed, coercivity and crystallite size exhibit both a regular and similar decrease when mechanical alloying time is increasing. In the case of Co–Ni alloy, a slight increase occurred after 72 h milling. The soft magnetic properties of the alloys (low values of both the squareness ratio M r / M s and the coercivity) indicate that small magnetic particles are typically single domain.