1. Department of Materials Science and Tsukuba Research Center for Energy Materials Science (TREMS), Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
2. Department of Physics, Faculty of Science and Engineering, Nusa Cendana University, Adisucipto street, Penfui Kupang, NTT 85001, Indonesia