Structural and magnetic properties of single-crystalline Co-doped barium titanate nanoparticles

Undoped and Co-doped BaTiO3 nanoparticles were synthesized by a one-step sol-precipitation method. For all the samples, X-ray diffraction showed characteristic diffraction lines for BaTiO3 without the indication of secondary phases. High-resolution transition electron microscopy images showed that BaTiO3 nanoparticles exhibit the nature of single-crystal. Magnetometry revealed that all the Co-doped BaTiO3 samples show paramagnetic behaviors and Co ions in BaTiO3 are present as isolated paramagnetic centers. This is contrasted to several reported cases of ferromagnetism in Co-doped BaTiO3.