1. School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China
2. Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin 150080, China
3. Division of Advanced Materials Engineering, Jeonbuk National University, Jeonju 54896, Korea
4. Department of Materials Science and Engineering, Pukyong National University, Busan 48513, Korea