Preparation and electromagnetic property of Al-doped SnO₂ powders by coprecipitation method in the GHz range

Al-doped SnO₂ powders have been prepared by coprecipitation method at 550 °C, using tin chloride (SnCl₄·5H₂O) as the raw material, ammonium hydroxide (NH₃·H₂O) as the precipitator, and aluminum nitrate (Al(NO₃)₃·9H₂O) as the doping source, respectively. The microstructure of the prepared powders has been characterized by X-ray diffraction and scanning electron microscope, respectively. Results show that the prepared powders were Sn_(1−x)Al_xO₂ (x = 0, 0.03, 0.06, and 0.09) solid solution powders and the lattice constant decreased with increasing Al doping content. The electromagnetic property in the frequency range of 8.2–12.4 GHz of prepared powders has been determined. The real part (ε′) and imaginary part (ε″) of permittivity of prepared powders increased with increasing Al doping content. There was little change of real part (μ′) and imaginary part (μ″) of permeability of prepared powders. The electromagnetic loss mechanism has been discussed.