Magnetic and Microwave Absorbing Properties of Co and Ti-Doped Sr M-Type Hexaferrites in the X-Band Frequencies

Hexagonal ferrites or hexaferrites are prominent class of materials in the applications of microwave and magnetic applications. Have been utilized widely for microwave passive components such as circulators, the versatility to dope with other chemical elements and its high permeability enable hexaferrites as a strong candidate in electromagnetic interference shielding application. In this study, an attempt to alter the magnetic properties and microwave responses of Sr M-type hexaferrites was conducted by substituting Fe atoms with Co and Ti atoms through mechanical alloying method. This work found that the introduction of the doping elements Co-Ti dramatically decreases the coercivity at Co Ti content x from 0 to 1, whereas, has little effect on the saturation mass magnetization. Two distinct dips of the reflection loss in the range of 7 to 13 GHz were observed for all samples. For the first dip, the effective absorption bandwidth does not differ significantly. At the second dip, a relatively broader effective absorption bandwidth is predicted extending the upper limit of the measurement at 13 GHz for samples x at 0.3, 0.5, and 1. In addition, a notable reflection loss of −31 dB was observed for sample x equal to 0.3.