University of Oulu

Huaicheng Xiang, Yang Bai, Chunchun Li, Liang Fang, Heli Jantunen, Structural, thermal and microwave dielectric properties of the novel microwave material Ba2TiGe2O8, Ceramics International, Volume 44, Issue 9, 2018, Pages 10824-10828, ISSN 0272-8842,

Structural, thermal and microwave dielectric properties of the novel microwave material Ba₂TiGe₂O₈

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Author: Xiang, Huaicheng1,2; Bai, Yang2; Li, Chunchun1,3;
Organizations: 1Ministry-province jointly-constructed cultivation base for state key laboratory of Processing for non-ferrous metal and featured materials, Key laboratory of new processing technology for nonferrous metals and materials ministry of education, College of Materials Science and Engineering, Guilin University of Technology, 541004, Guilin, China
2Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, FI-90014 Oulu, Finland
3Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: Elsevier, 2018
Publish Date: 2018-05-17


Rapid developments of microwave dielectric materials have emerged in recent years due to their wide-spread applications and the revolution in wireless communications. However, many commercial microwave materials are based on titanates, niobates and tantalates which have the disadvantages both of costly raw materials and high sintering temperatures. These result in a production process which is not energy efficient. In this paper we develop a BaO-TiO₂-GeO₂ ternary system derived from the BaO-TiO₂ binary system to obtain low temperature co-fired microwave dielectric ceramics for high frequency applications. The Ba₂TiGe₂O₈ ceramics were prepared via the conventional solid-state route. The X-ray diffraction results showed that Ba₂TiGe2O₈ belongs to the orthorhombic, Cmm2 space group. The ceramics exhibited a densification of 96.3% after being sintered at 1060 °C. They also exhibited a relative permittivity (εr) of 12.7, a quality factor (Q×f) of 9060 GHz (at 10 GHz), a temperature coefficient of resonant frequency (τf) of −30 ppm/°C and a coefficient of thermal expansion (CTE) of 11.0 ppm/°C. In addition, the Raman spectra and ionic polarizability of Ba₂TiGe₂O₈ unit cells were investigated.

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Series: Ceramics international
ISSN: 0272-8842
ISSN-E: 1873-3956
ISSN-L: 0272-8842
Volume: 44
Issue: 9
Pages: 10824 - 10828
DOI: 10.1016/j.ceramint.2018.03.127
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: This work was financially supported by Natural Science Foundation of China (Nos. 51502047, 21561008, and 21761008), the Natural Science Foundation of Guangxi Zhuang Autonomous Region (Nos. 2015GXNSFFA139003, 2016GXNSFBA380134, and 2016GXNSFAA380018), Project of Scientific Research and Technical Exploitation Program of Guilin (2016010702-2), and Innovation Project of Guangxi Graduate Education (YCBZ2017052). Author Y. Bai acknowledges the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. ‘‘705437’’.
EU Grant Number: (705437) NextGEnergy - Next Generation Power Sources for Self-sustainable Devices – Integrated Multi-source Energy Harvesters
Copyright information: © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license