1. State Key Laboratory of Electrical Insulation and Power Equipment and Multi‐disciplinary Materials Research Center Frontiers Institute of Science and TechnologyXi'an Jiaotong University Xi'an 710049 China
2. Center of Microstructure ScienceFrontier Institute of Science and TechnologyXi'an Jiaotong University Xi'an 710049 China
3. Electronic Materials Research LaboratorySchool of Electronic and Information EngineeringXi'an Jiaotong University Xi'an 710049 China
4. Multidisciplinary Materials Research CenterFrontier Institute of Science and TechnologyXi'an Jiaotong University Xi'an 710049 China
5. Ferroic Physics GroupNational Institute for Materials Science Tsukuba 305‐0047 Ibaraki Japan