TY  - JOUR
ID  - SisLab1796
UR  - http://dx.doi.org/10.1063/1.4907182
A1  - Phan, The Long
A1  - Pham, Duc Thang
A1  - T., A. Ho
A1  - T., V. Manh
A1  - Tran, Dang Thanh
A1  - V, D. Lam
A1  - N., T. Dang
A1  - S., C. Yu
Y1  - 2015///
N2  - We have prepared polycrystalline samples BaTi1?xCoxO3 (x?=?0?0.1) by solid-state reaction. X-ray diffraction and Raman-scattering studies reveal the phase separation in crystal structure as changing Co-doping content (x). The samples with x?=?0?0.01 are single phase in a tetragonal structure. At higher doping contents (x?>?0.01), there is the formation and development of a secondary hexagonal phase. Magnetization measurements at room temperature indicate a coexistence of paramagnetic and weak-ferromagnetic behaviors in BaTi1?xCoxO3 samples with x?>?0, while pure BaTiO3 is diamagnetic. Both these properties increase with increasing x. Analyses of X-ray absorption spectra recorded from BaTi1?xCoxO3 for the Co and Ti K-edges indicate the presence of Co2+ and Co3+ ions. They locate in the Ti4+ site of the tetragonal and hexagonal BaTiO3 structures. Particularly, there is a shift of oxidation state from Co2+ to Co3+ when Co-doping content increases. We believe that the paramagnetic nature in BaTi1?xCoxO3 samples is due to isolated Co2+ and Co3+ centers. The addition of Co3+ ions enhances the paramagnetic behavior. Meanwhile, the origin of ferromagnetism is due to lattice defects, which is less influenced by the changes caused by the variation in concentration of Co2+ and Co3+ ions.
The-Long , P. D. Thang2, T. A. 1, T. V. Manh1, Tran Dang Thanh1,3, V. D. Lam3, N. T. Dang4 and S. C. Yu
JF  - Journal Applied Physics
VL  - 117
TI  - Local geometric and electronic structures and origin of magnetism in Co-doped BaTiO3 multiferroics
AV  - none
ER  -