The Lowered Dielectric Loss and Grain‐Boundary Effects in La‐doped Y2/3Cu3Ti4O12 Ceramics. Issue 12 (13th November 2013)

• Record Type: Journal Article
• Authors: Liang, Pengfei; Chao, Xiaolian; Wang, Fang; Liu, Zhanqing; Yang, Zupei; Alford, N.
• Is Part Of: Journal of the American Ceramic Society. Volume 96:Issue 12(2013)
• Page Start: 3883
• Page End: 3890
• Publication Date: 2013-11-13
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.12644
• Languages: English
• ISSNs: 0002-7820

Abstract

<abstract abstract-type="main" id="jace12644-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The effects of La concentration on the electrical conductivity and electric modulus of Y<sub>2/3−<italic>x</italic></sub>La<sub><italic>x</italic></sub>Cu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> ceramics (0.00 ≦ <italic>x</italic> ≦ 0.20) were investigated in detail. Proper amount of La substitution in Y<sub>2/3−<italic>x</italic></sub>La<sub><italic>x</italic></sub>Cu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> ceramics made the dielectric loss decreased. When <italic>x </italic>= 0.10, Y<sub>2/3−0.10</sub>La<sub>0.10</sub>Cu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> ceramics exhibited the highest grain‐boundary resistance (0.893 MΩ) and the lowest dielectric loss (about 0.025 at 1 kHz), meanwhile the samples exhibited a relatively high dielectric constant above 6000 over a wide frequency range from 40 Hz to 1 MHz. The decreased dielectric loss was attributed to the enhanced grain‐boundary resistance. With the increase in La concentration, the dielectric relaxation behaviors correlated with the grain‐boundary effects were significantly enhanced. By La doping, the activation energies for the conduction in grain boundaries were slightly depressed, and the activation energies for the relaxation process in grain boundaries were slightly changed. Based on the activation values, it can be concluded that the doubly ionized oxygen vacancies <alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg3zmnbj0q" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:00027820:media:jace12644:jace12644-math-0001" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>V</mml:mi><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mo>∙</mml:mo><mml:mo>∙</mml:mo></mml:mrow></mml:msubsup></mml:math></alternatives> had substantial contribution to the conduction and relaxation behaviors in grain boundaries.</p> </abstract>