Terahertz dielectric response of ferroelectric baxsr1-xtio3 thin films

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 58; no. 11; pp. 2276 - 2280
• Main Authors: Kang, Seung Beom, Kwak, Min Hwan, Choi, Muhan, Kim, Sungil, Kim, Taeyong, Cha, Eun Jong, Kang, Kwang Yong
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.11.2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorption; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric constant; Dielectric loss and relaxation; Dielectric measurements; Dielectric properties of solids and liquids; Dielectric thin films; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Ferroelectricity and antiferroelectricity; Optical films; Physics; Substrates; Spectroscopy; Dielectric materials; Magnesium oxide; Dielectric properties; Pulsed laser deposition; Barium titanates; Relaxation time; Dielectric relaxation; Thickness; THz range; Ferroelectricity; Time domain method; Model matching; Optical properties; Strontium titanates; Modelling; Permittivity; Optical constants; Ferroelectric thin films
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2011.2084

Terahertz time-domain spectroscopy has been used to investigate the dielectric and optical properties of ferroelectric Ba x Sr 1-x TiO 3 thin films for nominal x-values of 0.4, 0.6, and 0.8 in the frequency range of 0.3 to 2.5 THz. The ferroelectric thin films were deposited at approximately 700 nm thickness on [001] MgO substrate by pulsed laser deposition. The measured complex dielectric and optical constants were compared with the Cole-Cole relaxation model. The results show that the Cole-Cole relaxation model fits well with the data throughout the frequency range and the dielectric relaxation behavior of ferroelectric Ba x Sr 1-x TiO 3 thin films varies with the films compositions. Among the compositions of Ba x Sr 1-x TiO 3 films with different Ba/Sr ratios, Ba 0.6 Sr 0.4 TiO 3 has the highest dielectric constants and the shortest dielectric relaxation time.