Al-substituted 𝑀-type hexaferrite is a highly anisotropic ferromagnetic material. In the present study, the coprecipitation and the citric-combustion methods of synthesis for SrAl₄Fe₈O₁₉ powders were explored and their microstructure, magnetic properties, and microwave absorptivity examined. X-ray diffraction (XRD), scanning electron microscopy (SEM), a vibrating sample magnetometer, and a vector network analyser were used to characterize the powders. The XRD analyses indicated that the pure SrAl₄Fe₈O₁₉ powder was synthesized at 900°C and 1000°C for 3 h by coprecipitation, but only at 1000°C for the citric-combustion processes. The SEM analysis revealed that the coprecipitation process yielded a powder with a smaller particle size, near single-domain structure, uniform grain morphology, and smaller shape anisotropy than the citric-combustion process. The synthesis technique also significantly affected the magnetic properties and microwave-absorptivity. Conversely, calcining temperature and calcining time had less of an effect. The grain size was found to be a key factor affecting the property of the powder. The powders synthesized by coprecipitation method at calcining temperature of 900°C exhibited the largest magnetization, largest coercivity, and best microwave absorptivity.

Transparent conductive ZnO : Al : Mo films with a molar ratio of Zn : Al : Mo = 99 : 0.99 : 0.01 were deposited on quartz glass substrate by a template-assisted sol-gel process and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and UV–Vis and luminescent spectrophotometries. The four types of organic template have induced nanowire morphology with varying aspect ratio. Dip coating in one constant positive and reverse direction causes the parallel array of ZnO : Al : Mo nanowires on the quartz glass substrate. Long and parallel arrayed nanowire films show obviously blue shifts and enhanced transmittances in the UV-Vis light range. The PEG-1000 and PEG-2000 have optimal effects among four templates as constant weight content is used. The films show strong ultraviolet, violet and bluish violet emissions. The templates also lead to overall thicker film and more native defect and thereby remarkably enhancing photoluminescence of the films. Long chain organic template can be used to optimize the optical properties of the doped ZnO film.