Synthesis and microwave absorbing properties of La‐doped Sr‐hexaferrite nanopowders via sol–gel auto‐combustion method

Abstract La‐doped Sr‐hexaferrite (Sr 1− x La x Fe 12 O 19 ) ( x = 0.05, 0.10, 0.15, 0.20) nanopowders with particle size ranging from 80 to 110 nm were successfully synthesized by sol–gel auto‐combustion. The phase formation temperature increases, while the particle size decreases as the La‐doping content goes up. The partial substitution of Sr 2+ by La 3+ results in the suppression effects on the growth‐up of the crystallites and the enhancement of the electron hopping between Fe 3+ with different valences, which leads to the improvement in the dielectric loss and magnetic loss. Therefore, both the microwave absorbing abilities and absorbing frequency ranges are tuned by La‐doping. The synthesized Sr‐hexaferrite nanopowders with doping element content of 0.10 demonstrate the fine broad microwave absorbing properties.