Preparation and characterization of multiferroic CoFe ₂O ₄/Bi _0.97Ce _0.03FeO ₃ coaxial nanotubes

Multiferroic CoFe ₂O ₄ (CFO)/Bi _0.97Ce _0.03FeO ₃ (BCFO) coaxial nanotubes were prepared by a sol-gel template method. Transmission electron microscopy revealed that the coaxial nanotubes featured with inner CFO and outer BCFO nanotubes. Selected area electron diffraction confirmed the coexistence of spinel CFO and perovskite BCFO phases in the coaxial nanotubes. Vibrating sample magnetometer measurements showed that the saturated magnetization of the coaxial nanotubes was 3.3 emu/g, smaller than that of CFO nanotubes. The P-E hysteresis loop of the coaxial nanotubes was of poor shape due to possible high conductivity in the inner CFO nanotubes. Dielectric measurements exhibited that the dielectric constant of the coaxial nanotubes decreased while the dielectric loss increased due probably to the small dielectric constant and high conductivity in the inner CFO nanotube. Ferroelectric and magnetic properties were simultaneously demonstrated in the CFO/BCFO coaxial nanotubes.