Abstract :
Microstructure and magnetic properties of Pr9Fe74Co12B5 and Pr9Fe74Co12GaB5 nanocomposite magnets have been investigated. The results of transmission electron microscope observations show that Ga addition obviously refines the microstructure of the ribbons, which may strengthen the exchange coupling interaction between the magnetically hard and soft phases. In this manner, the magnetic properties of the samples are significantly improved. For example, the maximum energy product of the Ga-doped sample increases by about 30% from 17 to 22.2 MGOe in comparison with that of the Ga-free one. In addition, due to Ga addition, coercivity mechanism of the ribbons is changed from the nucleation-type of reversed domain into the pinning-type of domain wall.
