Turky Ali Omar, Rashad Mohamed Mohamed, Kandil Abd El-Hakim Taha, Bechelany Mikhael
Central Metallurgical Research and Development Institute, P.O. Box: 87, Helwan, Cairo, Egypt.
Phys Chem Chem Phys. 2015 May 21;17(19):12553-60. doi: 10.1039/c5cp00319a.
Metal doped barium strontium titanate (BST; Ba0.5Sr0.5TixM1-xO3) nanopowders have been successfully synthesized through the oxalate precursor route based on low cost starting materials. The effect of metal ion substitution, namely Fe(3+), Mn(2+), Co(2+) and Y(3+), on the crystal structure, microstructure and optical, electrical, dielectric and magnetic properties of BST was studied. The results revealed that a crystalline single cubic BST phase was formed for pure and Mn(2+), Co(2+) and Y(3+) ion-substituted BST samples, whereas a tetragonal BST structure was obtained for the Fe(3+) substituted BST sample at an annealing temperature of 1000 °C for 2 h. Furthermore, addition of the metal ions was found to decrease the crystallite size and unit cell volume of the produced BST phase. The microstructure of the produced pure BST phase was metal ion dependent. Most BST particles appeared as a cubic like structure. The transparency of BST was found to increase with metal substitution. Meanwhile, the band gap energy was increased from 3.4 eV for pure BST to 3.8, 4.1, 4.2 and 4.3 eV as the result of substitution by Fe(3+), Mn(2+) and Co(2+) and Y(3+) ions, respectively. The DC resistivity was metal ion dependent. The highest DC resistivity (ρ = 66.60 × 10(5) Ω cm) was accomplished with the Mn(2+) ion. Moreover, the addition of metal ions decreased the dielectric properties of the expected Mn(2+) ion and increased the magnetic properties.
基于低成本的起始原料，通过草酸盐前驱体路线成功合成了金属掺杂的钛酸钡锶（BST；Ba0.5Sr0.5TixM1-xO3）纳米粉末。研究了金属离子取代，即Fe(3+)、Mn(2+)、Co(2+)和Y(3+)，对BST的晶体结构、微观结构以及光学、电学、介电和磁性能的影响。结果表明，纯的以及Mn(2+)、Co(2+)和Y(3+)离子取代的BST样品形成了结晶单立方BST相，而在1000℃退火2小时的条件下，Fe(3+)取代的BST样品获得了四方BST结构。此外，发现添加金属离子会减小所制备BST相的微晶尺寸和晶胞体积。所制备的纯BST相的微观结构取决于金属离子。大多数BST颗粒呈现出立方状结构。发现BST的透明度随着金属取代而增加。同时，由于分别被Fe(3+)、Mn(2+)、Co(2+)和Y(3+)离子取代，带隙能量从纯BST的3.4 eV增加到3.8、4.1、4.2和4.3 eV。直流电阻率取决于金属离子。Mn(2+)离子实现了最高的直流电阻率（ρ = 66.60×10(5)Ω·cm）。此外，添加金属离子降低了预期的Mn(2+)离子的介电性能并增加了磁性能。
