Papers by Author: Kai Lun Yao

Abstract: The electronic structures and magnetic properties of the compound Co(endi)2(N3)2 are studied by means of the first-principles method. According to the calculations, there is ferromagnetic interaction in the compound, and the magnetic coupling comes from the spin delocalization effect from Co2+ to the azide ligand. It is found that there is strong intralayer and weak interlayer magnetic couplings in the compound. It also reveals semi-metallically magnetic properties.

Abstract: Bi4-xLaxTi3O12 (BLT) ferroelectric thin films were deposited on Pt/Si substrates by RF magnetron sputtering with Bi4-xLaxTi3O12 (x=0.5, 0.75, 1) targets with 50-mm diameter and 5-mm thickness. The effects of La contents on microstructure and ferroelectric properties of Bi4-xLaxTi3O12 thin films were investigated. The grain growth behavior and ferroelectric properties such as remanent polarization were found to be dependent on the La contents in the BLT thin films.

Abstract: The ferroelectricity of Bi3.2Sm0.8Ti3O12 (BST) and Bi3.2Sm0.8Ti2.97V0.03O12 (BSTV)ceramics prepared at 1100oC by a conventional ceramic technique is investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BST ceramics are 16 µC/cm2 and 62kV/cm, respectively. Furthermore, V5+ substitution improves the Pr value of the BST ceramics up to 25µC/cm2, which is larger than that of the BST ceramics. Therefore, the co-substitution of Sm3+ and V5+ in Bi4Ti3O12 (BIT) ceramics is effective for the improvement of its ferroelectricity.