PREPARATION AND MAGNETIC-PROPERTIES OF ZN-DOPED FE3O4 MAGNETIC COLLOID

Fe3O4 magnetic colloids were produced by co-precipitating a Fe2+, Fe3, and Zn2+ containing solution with a NaOH solution at 70 degrees C. A nalyses results indicated that the Zn content of the Fe3O4 colloids wa s always less than the solution's Zn content. The difference res found to be the smallest when the colloid was precipitated at pH=10. The si gma s values of the Fe3O4 colloid significantly improved by adding an appropriate amount of Zn ions and precipitating it at an optimum pH va lue, pH=10. The optimum Zn ion content was 6.18 at%, which was corresp onded to Zn0.1854Fe0.8145Fe2O4. At this composition the colloid's sigm a(s) value was 94 emu/g, and increased by more than 34% of pure Fe3O4 colloid's sigma value. By theoretical calculation the sigma(s) should increase 27.8%.