Structure, Morphology, and Magnetic Properties of M-type Nb-doped Ferrite Prepared via Solid-state Sintering

BaFe12−xNbxO19 (x = 0.00, 0.04, 0.08, 0.12, 0.16, and 0.20) with a nominal composition for M-type hexagonal barium ferrite was prepared using solid-state sintering methods. The microstructure and magnetic properties of hexaferrite were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM), and vibrating-sample magnetometry (VSM). XRD results revealed that the crystal structure of barium ferrite remained intact after Nb doping, maintaining a single barium ferrite phase. FESEM confirmed the hexagonal crystal structure of the sample. Energy-dispersive X-ray spectroscopy showed increased Nb content and decreased Fe content without the formation of other elements. FTIR revealed bands at 598 and 445 cm−1 corresponding to tetrahedral and octahedral clusters, respectively. The VSM test showed that the saturation magnetization (Ms), residual magnetization (Mr), and coercivity (Hc) initially increased and then decreased with increasing Nb doping, reaching maximum values of 92.297 emu/g, 44.256 emu/g, and 3367.53 Oe, respectively, at x = 0.08.