The hard magnetic properties and microstructure evolution of the multilayer [NdFeBNbCu∕FeBSi]⋅n thin films

Abstract

The influence of the thickness of constituent layers and annealing conditions for multilayer [NdFeBNbCu∕FeBSi]⋅n thin films on the magnetic properties and microstructure is reported. The Nb–Cu combination inhibits the grain growth and promotes the formation of nucleation sites. The FeSiB layer insertion leads to a slight increase in the Curie temperature and to a rectangular hysteresis loop. As compared to Ta∕NdFeBNbCu (540nm)∕Ta single layer, the Ta∕[NdFeBNbCu(180nm)∕FeBSi(15nm)]⋅3∕Ta multilayer nanocomposite films exhibit very good magnetic properties such as squareness Mr∕Ms of about 0.92, maximum energy product of about 397kJ∕m3, and an increase in the Curie temperature of about 17°C due to stratification by using FeBSi film as space layer.