Probing Oxygen Defects in Na0.5Bi0.5TiO3 Ferroelectric by Micro‐Raman Spectroscopy

• Published in: physica status solidi (b) Vol. 255; no. 7
• Main Authors: Selvamani, Rachna, Singh, Gurvinderjit, Sathe, Vasant, Tiwari, Vidya Sagar
• Format: Journal Article
• Language: English
• Published: 01.07.2018
• Subjects: ceramics; ferroelectrics; oxygen defects; phonon vibration bands; Raman scattering
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201800002

Raman spectroscopy of Na0.5Bi0.5TiO3 ceramic is carried out at room temperature. In addition to well‐known Raman modes, two extra bands are also observed near 770 and 835 cm−1. Their presence is conjectured to the presence of oxygen defects in the crystal lattice. The intensity of these bands increases with an increase in oxygen defect concentration. It is proposed that Raman spectroscopy could be a useful tool for detecting the oxygen defects in Na0.5Bi0.5TiO3 based ferroelectrics. Micro‐Raman scattering of sodium bismuth titanate (NBT) is carried out. It shows the presence of unexpected phonon vibration modes between 750 and 900 cm−1. These modes are attributed to oxygen defects. The intensity of these modes depends upon concentration of oxygen defects. Raman spectroscopy is a simple and much faster technique than the impedance, EPR, and positron spectroscopy techniques used to detect oxygen defects. More importantly Raman spectroscopy also provides information about the defect dynamics.