Dy在BaTiO_3中的位占据研究

应用冷压陶瓷技术制备Dy分别掺杂在BaTiO3中的Ba位、Ti位和Ba/Ti位的陶瓷.采用X射线衍射(XRD)、拉曼光谱(RS)和电子顺磁共振(EPR)测试技术调查了Dy在BaTiO3中的位占据倾向.结果表明:Dy倾向于占据Ba位优于Ti位;无论在Ba位还是Ti位占据的名义配比下,Dy都以少量Dy3+形式不可避免地进入BaTiO3中的另一位.x=0.01时,(Ba1-xDyx)TiO3和(Ba1-xDyx)Ti1-x/4O3陶瓷出现很强的g=1.974的Ba空位缺陷信号.Ba(Ti1-xDyx)O3陶瓷在x=0.01时有第二相Ba12Dy4.67Ti8O35析出并且出现一个较弱的g=2.002的Ti空位缺陷信号.(Ba1-xDyx)(Ti1-xDyx)O3陶瓷的固溶度大于x=0.03,在825 cm-1处有较强的拉曼电荷效应.

Study on Site Occupation of Dy in BaTiO3

The cold-pressing ceramic technique was used to prepare BaTiOz ceramics doped with Dy at Basite, Ti-site, and Ba/Ti-sites, respectively. The site-occupation preference of Dy in BaTiO3 was investigated by X-ray diffraction （ XRD ） , Raman spectroscopy （ RS ） , and electron paramagnetic resonance （ EPR ） techniques. The results show that Dy prefers Ba-site to Ti-site. Under the nominal formula of whether Ba-site occupation or Ti-site occupation, Dy as Dy3 ＋ inevitably enters another site of BaTiO3. A strong g = 1. 974 EPR signal associated with Ba-vacancy defects appeared in （Ba1 _xDyx）TiO3 and （Bal-xDyx） Ti1 -x/4O3 ceramics at x = 0.01. A small amount of secondary phase was separated out from the main perovskite phase and indentified as Ba＋2Dy4 67Ti8035 when x = 0.01, accompanying a weak g = 2. 004 EPR signal associated with Ti-vacancy defects. The solubility limit of （ BaI -x Dy＋ ） （ Ti1-x DYx ） 03 ceramics was above x = 0.03 and a strong Raman charge effect was observed in the vicinity of 825 cm- 1 .