Synthesis and characterization of nonconventional nickel-titania glasses by sol-gel route

Glasses in the NiO-TiO<SUB>2</SUB> system in the composition range 15 to 25 mol% of NiO have been synthesized by the sol-gel technique by heat treatment of the precursor sol at 500°C. The glass structure is built up by crosslinking of two units, namely TiO<SUB>6</SUB> octahedron and NiO<SUB>3</SUB> triangle. Glassy structure is confirmed at a microscopic level by scanning electron microscopy. An increase in the values of peak-to-peak width of electron paramagnetic resonance with increasing concentration of Ni<SUP>2+</SUP> is attributed to an enhanced interaction between neighboring paramagnetic Ni<SUP>2+</SUP> ions