Dielectric relaxation studies on two-dimensional nanocomposites of NiS and Na-4 mica

Abstract

Na-4 mica template has been used to grow NiS nanosheets within the nanochannels with thickness ~0.6 nm. DC and ac electrical properties of the nanocomposite in a pellet-form have been measured over temperature range 313–473 K at frequencies from 10₂ to 10₆ Hz. The dc resistivity variation as a function of temperature has been explained as arising due to a parallel combination of NiS nanosheets and Na-4 mica grains. The activation energies of conduction have been found to be 0.23 and 0.45 eV in temperature ranges 323–363 K and 363–424 K, respectively. The frequency exponent s obtained from ac data has a value 0.7 which signifies a three-dimensional movement of the charge carriers involved. The dielectric modulus has been analyzed by two phase laminar conductor model proposed by Isard. The activation energies of dc resistivity and relaxation time are in reasonable agreement with each other in the different temperature ranges measured.