The memory effect of Dy2.8Sr0.2Fe5O12(DySrIG) nanoparticles

Dy2.8Sr0.2Fe5O12 (DySrIG) was prepared using the citrate-nitrate auto-combustion method. Single phase garnet with cubic structure was obtained at 1100 degrees C. Thermal hysteresis (heating-cooling) study was performed for the following physical properties: crystal structure using x-ray diffraction (XRD); magnetic susceptibility using Faraday's method; dielectric measurements including dielectric constant as well as ac conductivity using an LCR meter. The results of the study reveal hysteresis loops in all the parameters which agree with those appearing in differential scanning calorimetry (DSC), and the former were interpreted according to the accompanying changes in the structural characterizations. The study clarifies that the investigated nanoparticles of DySrIG possess an electric memory effect with thermalization, where their dielectric parameters have sensitive changes with temperature in the range 25-400 degrees C and return to their original values at room temperature again. Accordingly, DySrIG could be recommended in thermal electric sensor applications (thermistors).