In this work we report on the synthesis, the microstructural characterization, and the magnetic properties of similar to 7 nm bimagnetic core/shell nanoparticles prepared by seed-mediated growth high temperature decomposition of organometallic precursor. The nanoparticles are formed by an antiferromagnetic CoO core coated with ferromagnetic CoFe2O4 shell of 2-3 run of thickness. XRD and electron diffraction patterns show the reflections of the structure of the CoFe2O4 and CoO phases and Dark- and Bright-field TEM images provide evidence of the core shell morphology of the system. Magnetic measurements show that the system presents a remarkably large coercivity and high squareness (at 5 K, Hc = 27.8 kOe and M-r/M-s = 0.79), compared to CoFe2O4 single phase nanoparticles of comparable size. The enhancement of the effective anisotropy is attributed to the surface and interface exchange coupling effects.
Bimagnetic CoO Core/CoFe2O4 Shell Nanoparticles: Synthesis and Magnetic Properties
Elisabetta Agostinelli;Dino Fiorani
2012
Abstract
In this work we report on the synthesis, the microstructural characterization, and the magnetic properties of similar to 7 nm bimagnetic core/shell nanoparticles prepared by seed-mediated growth high temperature decomposition of organometallic precursor. The nanoparticles are formed by an antiferromagnetic CoO core coated with ferromagnetic CoFe2O4 shell of 2-3 run of thickness. XRD and electron diffraction patterns show the reflections of the structure of the CoFe2O4 and CoO phases and Dark- and Bright-field TEM images provide evidence of the core shell morphology of the system. Magnetic measurements show that the system presents a remarkably large coercivity and high squareness (at 5 K, Hc = 27.8 kOe and M-r/M-s = 0.79), compared to CoFe2O4 single phase nanoparticles of comparable size. The enhancement of the effective anisotropy is attributed to the surface and interface exchange coupling effects.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.