1. Liu S Q, Wu N J, Ignatiev A 2000 Appl. Phys. Lett. 76 2749
2. Zhuang W W, Pan W, Ulrich B D, Lee J J, Stecker J, Burmaster A, Evans D R, Hsul S T, Tajiri M, Shimaoka A, Inoue K, Naka T, Awaya N, Sakiyama K, Wang Y, Liu S Q, Wu N J, Ignatiev A 2002 IEEE. IEDM p193
3. Kim D C, Seo S, Ahn S E, Suh D S, Lee M J, Park B H, Yoo I K 2006 Appl. Phys. Lett. 88 202102
4. Yang J J, Pickett M D, Li X M, Ohlberg D A A, Stewart D R, Williams R S 2008 Nat. Nanotech. 3 429
5. Meng Y, Zhang P J, Liu Z Y, Liao Z L, Pan X Y, Liang X J, Zhao H W, Chen D M 2010 Chin. Phys. B 19 037304