Dielectric properties of RE2W2O9 (RE = Pr, Sm–Gd) ceramics. Issue 15 (December 2015)

• Record Type: Journal Article
• Authors: Urbanowicz, P.; Piątkowska, M.; Sawicki, B.; Groń, T.; Kukuła, Z.; Tomaszewicz, E.
• Is Part Of: Journal of the European Ceramic Society. Volume 35:Issue 15(2015:Dec.)
• Page Start: 4189
• Page End: 4193
• Publication Date: 2015-12
• Subjects: Monoclinic structure -- Electrical properties -- Dielectric spectroscopy; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2015.07.028
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: The UV–vis–NIR and electrical conductivity σ ( T ) measurements of RE2 W2 O9 (RE = Pr, Sm–Gd) showed the insulating state and the calculated value of the direct allowed energy gap E g > 3.5 eV. Thermoelectric power S ( T ) measurements showed the n-type conduction for Sm2 W2 O9 and Eu2 W2 O9 as well as p-type one for Pr2 W2 O9 and for Gd2 W2 O9 . The I – V characteristics, measured at 300 and 400 K, showed the symmetrical and linear behaviour of electron emission, slightly higher at higher temperature. Relative dielectric permittivity ɛ r as well as loss tangent (tan δ ) do not depend both on the temperature in the range of 76–400 K and the frequency in the range of 5 × 10 2 –1 × 10 6 Hz. ɛ r increases from 8 via 11 and 18 to 33 in the sequence: Gd, Eu, Pr and Sm, respectively. Since the loss factor is close to zero (tan δ < 0.005), the test materials can be considered a dielectric (with energy storage potential).