2021 Volume 129 Issue 9 Pages 566-573
The regulation of magnetic and dielectric properties for hexagonal barium ferrites by ion doping is highly desirable in magnetic recording and microwave absorption. Herein, aluminum (Al)-substituted barium hexaferrite with the general formula of BaFe12−xAlxO19 (x: 0, 0.6, 1,2, 1.8) was obtained. The influences of the Al3+ doping concentration on the crystal structure, microstructure, static magnetic, complex dielectric and permeability properties of hexagonal barium ferrites were studied. The morphologies and crystal structure characterizations confirm the Al3+ ion has effective doping in the hexagonal barium ferrites and substituted for Fe3+ in positions of 2b site. The lattice parameters and grain size of the hexagonal barium ferrites were dependent on the doping concentration. The magnetic characterization displays the saturation magnetization decrease while the coercivity increase with the doping concentration. The high-value about 8249 Oe of coercivity can be obtained at x = 1.8. The dielectric properties measurement further indicates that Al doping could improve both real and imaginary parts of permittivity. The highest value of the real part of permittivity was obtained at x = 1.2. Lastly, the complex permeability spectrum displayed the doping of Al ions not only regulate the complex permeability but also influence the domain wall resonance frequency, which is significant for controlling the application frequency.