Microstructures and magnetic properties of Co-substituted Ce–Fe–B amorphous alloys

Compare with Ce–Fe–B crystalline magnets, the amorphous alloy exhibit interesting properties due to their domains, low anisotropy energy, and microstructure contribution. In order to investigate magnetic properties and microstructures of the amorphous Ce–Fe–B system with Co substituting for Fe, the ribbons with a nominal composition of Ce_13.5(Fe_79.5-xCo_x)B₇ (x = 0, 3, 6, 9, 12) were prepared using vacuum melt spinner at a wheel speed of 50 m/s. The XRD and the corresponding SAED Pattern indicate the uniform amorphous microstructure is well maintained in each sample. These ribbons are magnetically soft and undergo a second order phase transition from ferromagnetic to paramagnetic state. With the increasing Co content, the Curie temperature almost linearly increases with temperature during 270 K and 410 K. Results from Lorentz Transmission Electron Microscopy (L-TEM) and micromagnetic simulation prove that the vortex domains can form spontaneously and stability in Ce–Fe–B amorphous materials no matter doping Co or not. The nontrivial topological domain structures found in experiments and numerical calculations have potential applications in the field of information storage, which is helpful to develop new applications of high abundance rare earth elements in functional materials.