Preparation and microwave absorption properties of Ce-substituted lithium ferrite

Ce-substituted lithium ferrite, Li0.5CexFe2.5−xO4 (x=0x=0, 0.015 and 0.15), was prepared from metal nitrates and citric acid by the citrate sol–gel method. The thermal decomposition process was investigated by TG-DSC. The phase composition and microstructure of Li0.5CexFe2.5−xO4 was characterized by X-ray powder diffraction analysis (XRD) and a transmission electron microscope (TEM). The complex permittivity and complex permeability and microwave absorption properties of Li0.5CexFe2.5−xO4–paraffin wax composite were measured by the transmission/reflection coaxial line method in the range of 2–18 GHz. It is shown that the substitution of cerium ion had a close effect on the properties of Li0.5CexFe2.5−xO4 ferrites. Also, the present investigation demonstrates that microwave absorbers for applications over 15 GHz, with satisfactory reflection loss, of more than −20 dB for specific frequencies, could be obtained by controlling the substituted Ce element.