Fine powders of Y3+ doped Ni0.4 Mg0.4 Cd0.2 Fe2-y O4 spinel nanoferrite (where y = 0.025 to 0.125) were prepared using a sol-gel autocombustion techniques and sintered at 400 o C for duration of 2 hrs. The analysis of XRD patterns revealed the formation of single phase cubic spinel structure. The lattice parameter and crystallite size decreases with increase in Y3+ concentration and average grain size was found to be between 17 to 24.3 nm. The dielectric properties have been studied as a function of frequency (100 Hz to 5 MHz) at room temperature using LCR meter and shown the normal dielectric behaviour. The value of ac conductivity increases with increase in frequency for all the compositions. TG-DTA analysis of the auto combusted ferrites was carried out with a heating rate of 10 ℃/min in air. These results may be applicable for promising area such as high frequency electrical devices.
