EFFECT OF SIZE ON MAGNETIC AND OPTICAL PROPERTIES OF Fe3O4 NANOPARTICLES

Abstract

In this paper, the influence of nanoparticle size on magnetic properties (saturation magnetization M_S, effective magnetic anisotropy K_eff) and optical properties (energy band gap E_g) were investigated. Magnetic nanoparticles Fe₃O₄ (FO) were synthesized by co-precipitation with different reaction temperatures of 50°C, 60°C, 70°C, and 80°C. They had sizes of 8.7 nm, 10.1 nm, 10.4 nm, and 11.9 nm, respectively. While the value of saturation magnetization M_S increased from 51.65 emu/g to 64.56 emu/g, their magnetic anisotropy value decreased from 18.26 kJ/m³ to 12.49 kJ/m³ when the value of diameter of magnetic nanoparticles Fe₃O₄ changed from 8.7 nm to 11.9 nm. In addition, the changing of the energy band gap E_g from 2.23 eV (~ 11.9 nm) to 2.75 eV (~ 8.7 nm) indicated the effect of nanoparticle size on optical properties for magnetic nanoparticles FO. The nanoparticle size is an important factor affecting the magnetic and optical properties of FO magnetic nanoparticles.