Preparation and properties of the CoFe ₂O ₄/Bi _3.15Nd _0.85Ti ₃O ₁₂ multiferroic composite coaxial nanotubes

The CoFe ₂O ₄ (CFO)/Bi _3.15Nd _0.85Ti ₃O ₁₂ (BNT) multiferroic composite coaxial nanotubes were prepared by a sol-gel template method. The morphologies of the coaxial nanotubes were characterized and the selected area electron diffraction patterns confirmed the coexistence of spinel CFO and perovskite BNT phase. The vibrating sample magnetometer measurements showed that the saturation magnetization and coercive field of the coaxial nanotubes were 1 emu/g and 0.7 kOe, respectively, which was contributed totally from the inner CFO nanotubes. The CFO/BNT coaxial nanotubes showed typical ferroelectric hysteresis loop, while the increased leakage current density is likely due to the high conductivity in the inner CFO nanotubes. Our study demonstrated that the CFO/BNT coaxial nanotubes were of both ferroelectric and magnetic features in nanoscale.