Direct observation of local structure distortion in Pb(MgNb)O by X-ray fluorescence holography
蛍光X線ホログラフィによるPb(MgNb)Oの局所ひずみの直接観測
Hu, W.; 林 好一*; 八方 直久*; 大和田 謙二; Chen, J.*; Ye, Z.-G*; 細川 伸也*; 高橋 正光
Hu, W.; Hayashi, Koichi*; Happo, Naohisa*; Owada, Kenji; Chen, J.*; Ye, Z.-G*; Hosokawa, Shinya*; Takahashi, Masamitsu
The chemical ordering regions (CORs) and polar nanoregions (PNRs) in relaxor ferroelectrics have been long believed to the origin of their high and temperature-independent permittivities. In the present work, we carried out X-ray fluorescence holography (XFH) experiments of Pb(MgNb)O (PMN) and La-doped PMN (2 at% La, PLMN) single crystals, which are prototype relaxor ferroelectric material, and investigated the local structure around Nb atoms at BL22XU of SPring-8. The La-doped PMN single crystal shows much bigger CORs than pure PMN. Nb K (16.6 keV) fluorescent X-rays were analyzed and focused on an avalanche photodiode detector with a cylindrical graphite-crystal energy analyzer. The results indicate that both Pb-site and Mg/Nb-site atoms have big fluctuations in PMN system and 1st neigher Pb atoms tend to shift toward central Nb atom along [111] direction.