Effect of zirconium content on exchange coupling and magnetization reversal of nanocrystalline Nd12.3Fe81.7–xZrxB6 alloy

The effect of Zr content on exchange coupling and magnetization reversal of the Nd12.3Fe81.7–xZrxB6 (x=0–3.0) ribbons was systematically investigated. Interaction domains were imaged by magnetic force microscopy (MFM). The strength of interactions determined by Wohlfarth's analysis increased first with Zr content x increasing, reached the maximum value at x=1.5, and then decreased with x further increasing. Initial magnetization curves and dependence of coercivity and remanence on applied magnetic field showed that the mechanism of coercivity in all samples was mainly of exchange coupling pinning type, which was enhanced with x increasing. It was found by three-dimensional atom probe (3DAP) that Zr atoms did not partition into the Nd2Fe14B hard magnetic phase, but significantly enriched at the interfacial region.