Microstructure and magnetic microstructure of the Pr60Al10Ni10Cu20−xFex (x=0, 4, 10, 15, 18) alloys observed by magnetic force microscopy

Abstract The microstructure and magnetic microstructure of the Pr 60 Al 10 Ni 10 Cu 20− x Fe x ( x =0, 4, 10, 15, 18) alloys have been achieved simultaneously by employing a magnetic force microscope directly on the as-cast cylinder rod surface for the first time. By varying the content of Fe, the microstructure of the Pr-based alloy changes progressively from a full glassy state to a composite state with nanocrystalline particles embedded in the glassy matrix, and finally into a nanostructured state. The accompanying magnetic property gradually changes from paramagnetic to hard. The experiment directly evidences the existence of exchange coupling between the crystallites and the variety of the grain-size-dependent magnetic properties can be well explained by Loffler et al.'s new random-anisotropy model (Loffler, et al., Phys. Rev. Lett. 85 (9) (2000) 1990).