Electrical conductivity and magnetic properties of core-shell silver-coated magnetite composite nanoparticles

Electrical conductivity and magnetic properties of core-shell silver-coated magnetite composite nanoparticles prepared by electroless deposition of silver on magnetite nanopowder are found to be affected mainly by the pressure used when preparing the nanoparticles sample cylinder and the Ag content in the nanoparticles. The electrical conductivity can be enhanced by increases of both the pressure and the Ag content. Direct current volume electrical resistivity of the nanoparticles with 40 wt% silver content is close to the order of 10(-4) Omega cm when the pressure is larger than 1 x 10(6) Pa. The saturation magnetization of the nanoparticles almost reduces linearly with increasing the silver content. According to the rule of mixtures, the resistivity of the nanoparticles is calculated. But it shows that the calculated values have a large deviation with the corresponding measured ones. As a comparison, resistivity and saturation magnetization of the mixtures consisting of silver and magnetite nanopowder are also measured. It will be an effective method to adjust the electromagnetic properties of the nanoparticles by changing the silver content.