Particle size effects on the magnetic behaviour of 5 to 11 nm Fe3O4 nanoparticles coated with oleic acid

8th International Conference on Fine Particle Magnetism

Chesnel, K.^1 ; Trevino, M.^1 ; Cai, Y.^1 ; Hancock, J.M.^2 ; Smith, S.J.^2 ; Harrison, R.G.^2

Department of Physics and Astronomy, BYU, Provo, 84602, UT, United States^1

Department of Chemistry and Biochemistry, BYU, Provo, 84602, UT, United States^2

关键词: Blocking temperature;    Fe3O4 nanoparticles;    Magnetic behaviour;    Magnetization loops;    Nanoparticle (NPs);    Particle size effect;    Superparamagnetics;    Zero-field cooling;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/521/1/012004/pdf
DOI  :  10.1088/1742-6596/521/1/012004

来源: IOP

【 摘 要 】

The magnetic behaviour of 5 to 11 nm magnetite (Fe3O4) nanoparticles (NPs) was measured at various temperatures (Ts) from 20 to 400 K. The particles were fabricated via thermal decomposition of an iron precursor, and involved a coating of the particles with oleic acid. The particle size distribution was analysed by XRD measurements and TEM imaging. Magnetization loops, measured at various Ts, indicate a superparamagnetic behaviour at high T and the occurrence of hysteresis at low T, with a stronger coercivity for the larger particles. Zero-Field-Cooling (ZFC) and Field Cooling (FC) curves indicate a superparamagnetic behaviour, with a blocking temperature varying significantly with the particle size. Namely, the peak temperature, Tmax, increases from 30 K to 170 K when the particle size increases from 5 nm to 11nm. Magnetic couplings between particles appear stronger for larger particles.