Abstract:

 Nanoparticles of pure and iron (5 % and 10 %), cobalt (2%, 5% and 10%) doped cadmium  selenide (CdSe) and nickel (5%, 7% and 10%) doped cadmium telluride (CdTe ) have been synthesized by soft chemical route. The particle size and the nano ‒crystalline nature of the  materials are confirmed using transmission electron microscopy and scanning electron microscopy. X- ray diffraction patterns show the structure of the p repared samples. The band gap of the materials is obtained using Tauc relation to UV - visible spectra. The Raman and infra- red spectra of the samples are analyzed to obtain the vibrational modes of the samples.  Kissinger equation is applied to the thermo-gr ams of differential scanning calorimeter to  calculate the activation energy of pure and doped nanoparticles. The frequency dependence of the dielectric response of the materials has been investigated using alternating current  impedance spectroscopy at vari ous temperatures. The most probable relaxation times obey the Arrhenius law. An analysis of real and imaginary parts of the dielectric constant has been  performed by considering the distribution of relaxation times. The complex impedance plane  plot has been analyzed by an equivalent circuit consisting of two serially connected             R -CPE units, each containing a resistance (R) and a constant phase el ement (CPE). The observed  electrical data are analyzed in the impedance and conductivity formalisms. The frequency  dependent conductivity spectra at various temperatures follow the Jonscher’s power law.  Field dependent (M-H) and temperature dependent (M - T) magnetization study of the samples has been carried out at room temperature and low temperature. Curie - Weiss temperature θ of the samples has been estimated from 1/ χ  vs.  T plots.