Size dependent anomalous dielectric behavior in nanoparticle Gd$_{2}$O$_{3}$ : SiO$_{2}$ glass composite system

Gd$_{2}$O$_{3}$ (0.5 mol{\%}) nanoparticles have been synthesized in a silica glass matrix by the sol-gel method at calcination temperatures of 700 $^{\circ}$C and above. Compared with the parent material SiO$_{2}$, this nano-glass composite system shows enhancement of dielectric constant and diffuse phase transition along with magnetodielectric effect around room temperature. Observed conduction mechanism is found to be closely related to the thermally activated oxygen vacancies. Magnetodielectric behavior is strongly associated with magnetoresistance changes, depending on the nanoparticle size and separation. Such a material might be treated as a potential candidate for device miniaturization.