BiFeO 3-CoFe 2O 4 composite thin films were formed on Pt/Ti/SiO 2/Si(100) substrates by chemical solution deposition from a mixed precursor solution. X-ray diffraction and transmission electron microscopy analyses confirmed that CoFe 2O 4 nanoparticles less than 10 nm were uniformly distributed in the BiFeO 3 matrix. The BiFeO 3-CoFe 2O 4 composite films exhibited the same ferroelectric switching charge as BiFeO 3 thin films, although a larger applied electric field was necessary. However, the magnetic properties were significantly improved by incorporation of CoFe 2O 4 nanoparticles into BiFeO 3; a saturated magnetization of 80 emu/cm 3 and a magnetic coercive field of 450 Oe were attained at 300 K. Furthermore, the composite films did not show superparamagnetic behavior in zero-field-cooling and field-cooling measurements, which suggest that the thermal fluctuation of CoFe 2O 4 nanoparticles was suppressed by exchange coupling with BiFeO 3.
ASJC Scopus subject areas
- Physics and Astronomy(all)