SUPERPARAMAGNETIC IRON COBALT ALLOY AND SILICA NANOPARTICLES OF HIGH MAGNETIC SATURATION AND A MAGNETIC CORE CONTAINING THE NANOPARTICLES

摘要

Thermally annealed superparamagnetic core shell nanoparticles of an iron-cobalt alloy core and a silicon dioxide shell having high magnetic saturation are provided. A magnetic core of high magnetic moment obtained by compression sintering the thermally annealed superparamagnetic core shell nanoparticles is also provided. The magnetic core has little core loss due to hysteresis or eddy current flow.

主权项

1. A thermally annealed superparamagnetic core shell nanoparticle, comprising:
a superparamagnetic core of an iron cobalt alloy; and a shell of a silicon dioxide directly coating the core; wherein a diameter of the iron cobalt alloy core is 200 nm or less, the core shell particle is obtained by a process comprising: wet chemical precipitation of the core; coating of the core with a silicon dioxide shell to obtain a thermally untreated core shell nanoparticle having a magnetic saturation (Ms); and thermal annealing of the untreated core shell nanoparticle to obtain the thermally annealed superparamagnetic core shell nanoparticle having a magnetic saturation (TAMs); wherein TAMs is equal to or greater than 1.25Ms.