Electromagnetic Wave Absorption Properties of La-Doped Strontium M-Type Hexagonal Ferrite in a 18-40 GHz Frequency Range

This article examines the performance of the M-type lanthanum-doped strontium hexaferrite with general formula Sr1-yLayFe12O19 (y=0.00, 0.10, 0.15, 0.20 and 0.25) as microwave absorbing materials in a 18-40 GHz frequency range. All the synthesized ferrites exhibited minimum reflection loss (RL) peaks with absorption greater than 90%. The multi-resonance imaginary part of complex permittivity ('') and complex permeability (mu '') contributed to a minimum RL peak with enhancement in the -10-dB bandwidth. Minimum RL of -22 dB, -27.14 dB, -27 dB and -30 dB with a -10-dB absorption bandwidth of 2.2 GHz, 2.3 GHz, 1.4 GHz and 2 GHz was obtained for composition y=0.10, y=0.15, y=0.20 and y=0.25, respectively, in the K-band. The absorption bandwidth (-10 dB) was further enhanced to 3.43 GHz, 2.62 GHz, 3.93 GHz and 2.3 GHz for these compositions, respectively, in the Ka-band. The synthesized ferrites have a high potential to be used as efficient microwave absorbers.