Cluster glass structure in nanohybrids of nonstoichiometric zinc ferrite in silica matrix

A cluster glass structure has been observed to occur in nanohybrids consist ing of zinc ferrite in an amorphous silica matrix. Such a unique cluster gl ass structure has been supported by studies of x-ray diffraction, transmiss ion electron microscopy, Fourier transform infrared spectroscopy, and magne tic characterization. By increasing the Fe/Zn ratio in silica gel to 10, cr ystallites of zinc ferrite of partially inverted structure were nucleated a nd grown in amorphous iron oxide pockets dispersed in the silica network. T he zinc ferrite crystallites, together with the confinement of silica matri x, suppress nucleation and crystallization of alpha -Fe2O3 to a temperature above 900 degreesC, preserving the cluster glass structure. The resulting cluster glass structure consists of amorphous iron oxide pockets of similar to 10 nm in dimensions together with zinc ferrite crystallites of similar to3 nm in sizes, which are uniformly dispersed in the amorphous silica glas s matrix. (C) 2001 American Institute of Physics.