1. a Department of Convergence Materials Science and Engineering , Changwon National University , Gyeongnam , 641-773 , Republic of Korea
2. b Department of Electrical Engineering , Changwon National University , Gyeongnam , 641-773 , Republic of Korea
3. c Department of Physics , Changwon National University , Gyeongnam , 641-773 , Republic of Korea
4. d Department of Materials Science and Engineering , Pohang University of Science and Technology , Gyeongbuk , 790-784 , Republic of Korea