Synthesis of Fe2O3 concentrations and sintering temperature on FTIR and magnetic susceptibility measured from 4 to 300 K of monolith silica gel prepared by sol–gel technique

Nano-crystalline ferric oxide was synthesized inside an amorphous silica matrix by the sol–gel method. The formation of ferric oxide can be detected, giving fine particles around 5–10 nm crystallite sizes calculated from win-fit program. This is associated with a specific role of the silica matrix, which facilitates the diffusion of the reacting cations, enhancing the ferric oxide formation. γ- to α- and/or ε-Fe2O3 transformations take place by increasing the Fe2O3 concentration for samples sintering at constant-heat treatment temperature. The dried monolith gel materials were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), as well as by scanning electron microscopy (SEM). The magnetic susceptibility at zero-field cooling (MZFC) of the prepared samples was evaluated using superconducting quantum interference device (SQUID) magnetometer in temperature range from 4 to 300 K at 1 T.