掺杂(Fe、Nb)SrTiO_3晶界组成的电子能量损失谱(EELS)分析

Grain boundary analysis by the electron energy loss spectroscopy (EELS)of SrTiO_3 doped with Fe^(3+),Nb^(5+)

采用高空间分辨率扫描透射电镜(STEM)对掺杂(Fe3+、Nb5+)SrTiO3晶界进行了观察,并利用采集的电子能量损失谱(EELS)对晶界组成进行了分析.结果表明,掺杂Fe的SrTiO3陶瓷晶界存在1nm左右的非晶膜,同晶体内部相比晶界缺Sr;三叉晶界为钛基玻璃相,Ti、O及Fe含量明显高于晶界.掺Nb的SrTiO3陶瓷晶界同晶粒相比同样缺Sr,三叉晶界主要以SiO2非晶相为主.Fe3+、Nb5+对Ti4+的替位及在晶界的偏析引起SrTiO3晶格畸变是导致晶界组成变化的主要原因.

The Electron Energy Loss Spectrum(EELS)of grain boundary composition of SrTiO 3 doped with Fe 3+ ,Nb 5+ was studied by using a high spatial resolution Scanning Transmission Electron Microscope(STEM).The results showed that grain boundaries of SrTiO 3 doped with Fe 3+ were covered with an amophous film,where Sr content is lower than the bulk levels,and tripplepockets were filled with titanium-based glass phase accompanying Ti,O and Fe content higher than grain boundaries.The grain boundaries of SrTiO 3 doped with Nb 5+ had lower Sr content than bulk grains too.The tripplepockets were dominated by a SiO 2 amorphous phase.The composition change in grain boundarie of SrTiO 3 were mainly due to Fe 3+ (Nb 5+ )substituting for Ti 4+ and segregation of Fe 3+ (Nb 5+ )on grain boundaries,which led to a severe distortion of grain cells of SrTiO 3 .