Enhanced coercivity in thermally processed „Nd,Dy...„Fe,Co,Nb,B...5.5/a-Fe nanoscale multilayer magnets

Structural and magnetic properties of laminated sNd,DydsFe,Co,Nb,Bd5.5 /Fe nanocomposites are investigated. Normally, the addition of the soft phase to the hard phase enhances the remanence but deteriorates the permanent-magnet performance of the material by reducing the coercivity. In the present system, the coercivity increases to 1608 kA/m s20.2 kOed in thermally processed Nd–Dy–Fe–Co–Nb–Bs15 nmd /Fes4 nmd multilayered nanocomposites, which is higher than that of the single-layer hard-magnetic film. The abnormally high coercivity is achieved by annealing at relatively high temperature, which breaks the laminated structure of the as-deposited multilayer. A likely physical explanation of the enhanced coercivity is the introduction of the domain-wall pinning sites that counteract the inevitable decrease of the nucleation field. © 2005 American Institute of Physics. fDOI: 10.1063/1.1905788g