Magnetic and microwave absorbing properties of Al and Zn substituted barium hexaferrites in X-band region

In this study, the Al and Zn substituted barium hexaferites with x = 0, 0.5, and 1 were prepared using wet mechanical alloying along with calcination at 1200°C and sintering at 1250°C. X-ray diffraction (XRD) characterization shows that single phase of M-type barium hexaferrites are formed in substitution amount x 0 and 0.5, and there are W-type barium hexaferrites peaks detected at x = 1. The addition of AlZn decrease the coercivity from 1.721 to 0.986 kOe at x = 0 and 1 respectively. Increasing the composition from x = 0.5 to x = 1 also reduce the magnetization saturation significantly. The microwave absorption of the prepared AlZn substituted barium hexaferrites with thickness 2 mm in X-band region is still relatively low, the maximum return loss is achieved when substitution amount x is 1 with value of 12.2 dB at 10.5 GHz. Increasing the substitution amount x of AlZn from 0 to 1 only slightly increases the value of return loss and shifts to lower frequencies.