Membrane-assisted synthesis of selected mixed-metal ferrite nanotubes using sol-gel derived precursors

An aqueous sol-gel process was applied for a membrane-assisted synthesis of selected mixed-metal ferrite (yttrium iron garnet (Y3Fe5O12, YIG), yttrium iron perovskite (YFeO3, YIP) and terbium iron perovskite, TbFeO3, TIP)) nanotubes. It was demonstrated that the phase purity of obtained nanotubes depends on the nature of the mixed-metal ferrite and final annealing temperature. Scanning electron microscopy and transmission electron microscopy, however, showed that well-defined nanotube structures were formed, even when the synthesis product was composed of different phases. Approximate nanotube size was evaluated from SEM measurements. Nanotubes with average diameter of 120–155 nm and wall thickness at about 15–50 nm were synthesized using the sol-gel membrane-assisted method. Mössbauer spectroscopy and magnetic measurements for the end products were also carried out.