1. Department of Materials Science & Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
2. Memory Thin Film Technology Team, Giheung Hwaseong Complex, Samsung Electronics, 1, Samsungjeonja-ro, Hwaseong-si, Gyeonggi-do 18448, Republic of Korea
3. School of Material Science and Engineering, Kumoh National Institute of Technology, 61, Daehak-ro, Gumi-si, Gyeongbuk 39177, Republic of Korea