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

Abstract

This article examines the performance of the M-type lanthanum-doped strontium hexaferrite with general formula Sr_1–yLa_yFe₁₂O₁₉ (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 (ɛ′′) and complex permeability (μ′′) 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.