Electron Paramagnetic Resonance Spectra of Pr4+Ions Doped in Pyrochlore-Type Compounds La2Sn2O7and La2Zr2O7

✍ Scribed by Keitaro Tezuka; Yukio Hinatsu

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 198 KB
• Volume: 143
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.8106

✦ Synopsis

The electron paramagnetic resonance spectra of powders with the Pr 4؉ ions doped in the B sites of the pyrochlore-type compounds A 2 B 2 O 7 (A ‫؍‬ La; B ‫؍‬ Sn or Zr) were successfully measured at 4.2 K. A very large hyperfine interaction with the 141 Pr nucleus was observed. The spectra were isotropic, which indicates that the symmetry of the oxygen coordination around Pr 4؉ ions is almost octahedral. The results were analyzed based on the weak field approximation, and the g values and hyperfine coupling constants A were obtained. The measured g values are smaller than "؊10/7" (which is calculated for the 7 ground doublet in the 2 F 5/ 2 multiplet), showing that the crystal field is effective to some extent on the behavior of a 4f electron in solids. The value of " g " decreases from 1.270 (Pr 4؉ /La 2 Zr 2 O 7 ) to 1.262 (Pr 4؉ /La 2 Sn 2 O 7 ), which is caused by the increase of the crystal field due to shrinking of the lattice. On the other hand, the hyperfine coupling constants are the same: A ‫؍‬ 0.076 (1) cm ؊1 .