MAGNETIC NANOPARTICLES

摘要

Nanoparticle sized metal or alloy is synthesized through a reverse micelle system which includes the steps of a) forming a concentrated aqueous solution of transition metal salts with platinum salts b) dispersing the metal salt solution in a non aqueous solution of a surfactant c) adding a reducing agent to reduce the metal salts to metallic alloy nano-particles in the absence of oxygen d) separating the metallic alloy nanoparticles 1s) heating the metallic alloy nanoparticles under controlled time, atmosphere and temperature conditions sufficient to form particles of a desired size and magnetic characteristics . The, precipitated metal or alloy nanoparticle has an average size of 3nm and is superparamagnetic. Through controlled annealing treatment, the magnetic characteristics of the nanoparticles can be manipulated to achieve specific values in the final product that is suitable for predetermined applications. The nanoparticles exhibiting superparamagnetism are suitable for magnetic bio-bead applications. Weakly ferromagnetic magnetic alloy nanoparticles are suitable for actuator applications. The strongly ferromagnetic magnetic alloy nanoparticles exhibiting high coercivity can be potential candidate for magnetic data storage applications.