Gd Mssbauer spectroscopic and powder X-ray diffraction study of CeO - GdO solid solution

セリアーガドリニア固溶体系のGdメスバウアー分光法及び粉末X線回折法による研究

中村 彰夫; 今井 和貴*; 井川 直樹   ; 岡本 芳浩  ; 山本 悦嗣  ; 松川 史郎*; 高橋 正*

Nakamura, Akio; Imai, Kazutaka*; Igawa, Naoki; Okamoto, Yoshihiro; Yamamoto, Etsuji; Matsukawa, Shiro*; Takahashi, Masashi*

Powder X-ray diffractometry and Gd-Mssbauer spectroscopy have been applied to the CeGdO prepared at 1450C. The former shows that this system forms a complete solid solution being the disordered defect-fluorite type in the smaller y range than 0.30 and the order C-type beyond y = 0.30. Its marked positive non-Vegardianity was consistently interpreted as a generalized Vegard-law behaviour of this distortion-dilated solid solution having Gd - oxygen vacancy association. The latter also clarifies that in the ordered C-type phase with decreasing y the 8b-site Gd-Mssbauer intensity steadily diminishes and vanishes at y = 0.50, indicating that the more-distorted minor 8b Gd in C-type GdO is being preferentially replaced with Ce.