Fabrication of crystalline bismuth-substituted yttrium iron garnet nanofibers via sol–gel and calcination-assisted electrospinning

The present report describes a model system for the fabrication of crystalline magnetic garnet nanofibers, and provides a universal routine to the fabrication of other ternary inorganic oxide nanofibers. Crystalline bismuth-substituted yttrium iron garnet nanofibers of several micrometers in length and of 100–200 nm diameter are prepared by sol–gel and calcination-assisted electrospinning, using a viscous sol–gel precursor solution composed of PVP/(Fe(C11H19O2)3+Y(OOC10H19)3+Bi(TMHD)3). A 15 kV DC voltage is applied to the needle, with a 0.5 ml/h feeding rate of the precursor solution, during the electrospinning process. Scanning electron microscopy, transmission electron microcopy, X-ray diffraction and magnetization process measurements were performed on the fibers. The composition of the sol–gel precursor solution and the role of the surrounding humidity, which gave optimal results when maintained below 50%, were found to be critical factors during the electrospinning processes.