EPR and ENDOR study of an oxygen-vacancy-associated Ti3+ center in RbTiOPO4 crystals

✍ Scribed by Yongquan Jiang; L.E. Halliburton; M. Roth; M. Tseitlin; N. Angert

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 311 KB
• Volume: 400
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2007.07.006

✦ Synopsis

The dominant Ti 3+ trapped electron center in flux-grown RbTiOPO 4 (RTP) crystals has been characterized using electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR). This center is produced during an X-ray irradiation at room temperature when a Ti 4+ ion traps an electron and becomes a Ti 3+ ion, and is best studied in the 30-40 K range. The EPR spectrum contains a three-line hyperfine pattern from two nearly equivalent neighboring 31 P nuclei, along with hyperfine lines from the 47 Ti and 49 Ti nuclei. The g matrix, determined from the angular dependence of the EPR spectrum, has principal values of 1.819, 1.889, and 1.947. Hyperfine matrices for four 31 P nuclei are obtained from the angular dependence of the ENDOR spectrum. The proposed model for this defect is a Ti 3+ ion adjacent to an oxygen vacancy at an OT position. Analogies are made to a similar Ti 3+ center in KTiOPO 4 (KTP) crystals.