Core-shell structure and dielectric properties of (K sub(0.5) Na sub(0.5))NbO sub(3)-SrZrO sub(3) for high-temperature capacitors

• Published in: Japanese Journal of Applied Physics Vol. 55; no. 10; p. 10TB08
• Main Authors: Aman, Sanshiro, Kubo, Keiko, Akiba, Hiroki, Iwanaga, Daisuke
• Format: Journal Article
• Language: English
• Published: 01.10.2016
• Subjects: Capacitors; Core-shell structure; Curie temperature; Dielectric constant; Dielectric properties; Multilayers; Resistivity; Sintering
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.55.10TB08

The microstructure and dielectric properties of (K sub(0.5) Na sub(0.5))NbO sub(3)-SrZrO sub(3) were investigated. The dielectric constant is high and stable in a wide temperature range. The rate of change in dielectric constant is within + or -10% in the temperature range from ?55 to 200 [degrees]C. This effect is thought to be due to the core-shell structure composed of a K-rich shell and a Na-rich core, which have different Curie temperatures. This core-shell structure can be controlled on the basis of sintering temperature. The width of the K-rich shell of a sample sintered at 1250 [degrees]C is larger than that of a sample sintered at 1180 [degrees]C. In addition, the insulation resistance of this material is high at high temperatures. The specific resistance of this material is 10 super(9)[Omega] cm at 200 [degrees]C. This material can be used for high-temperature multilayer ceramic capacitors, which have stable capacitance and high reliability at high temperatures.