[1] Brinkman A, Huijben M, Vanzalk M, Huijben J, Zeitler U,
Maan J C, Vanderwiel W G, Rijnders G, Blank D H A and Hilgenkamp H
2007 Nature Mater. 6 493

[2] Ahn C H, Rabe K M and Triscone J M 2004 Science
303 488

[3] Ohtomo A and Hwang H Y 2004 Nature 427 423

[4] Wang J, Neaton J B, Zheng H, Nagarajan V, Ogale S B, Liu
B, Viehland D, Vaithyanathan V, Schlom D G, Waghmare U V, Spaldin N
A, Rabe K M, Wuttig M and Ramesh R 2003 Science 299 1719

[5] Mitra C, Raychaudhuri P, Dorr K, M\"{uller K H, Schultz
L, Oppeneer P M and Wirth S 2002 Phys. Rev. Lett. 90
017202

[6] Lu H B, Yang G Z, Chen Z H, Dai S Y, Zhou Y L, Jin K J,
Cheng B L, He M, Liu L F, Guo H Z, Fei Y Y, Xiang W F and Yan L 2004
Appl. Phys. Lett. 84 5007

[7] Jin K J, Lu H B, Zhou Q L, Zhao K, Cheng B L, Chen Z H,
Zhou Y L and Yang G Z 2005 Phys. Rev. B 71 184428

[8] Lu H B, Dai S Y, Chen Z H, Yang G Z, Zhou Y L, He M, Liu L
F, Guo H Z, Fei Y Y and Xiang W F 2005 Appl. Phys. Lett.
86 032502

[9] Jin K J, Zhao K, Lu H B, Liao L and Yang G Z 2007
Appl. Phys. Lett. 91 081906

[10] Mckee R A, Walker F J and Chisholm M F 2001 Science
293 468

[11] Lee H N, Hesse D, Zakharov N and G\"{osele U 2002
Scence 296 2006

[12] Eisenbeiser K, Finder J M, Yu Z, Ramdani J, Curless J A,
Hallmark J A, Droopad R, Ooms W J, Salem L, Bradshaw S and Overgaard
C D 2000 Appl. Phys. Lett. 76 1324

[13] Hao J H, Gao J, Wang Z and Yu D P 2005 Appl. Phys.
Lett. 87 131908

[14] Hunter D, Lord K, Williams T M, Zhang K, Pradhan A K,
Sahu D R and Huang J L 2006 Appl. Phys. Lett. 89 092102

[15] Zhao K, Huang Y H, Zhou Q L, Jin K J, Lu H B, He M, Cheng
B L, Zhou Y L, Chen Z H and Yang G Z 2005 Appl. Phys. Lett.
86 221917

[16] Liu G Z, Jin K J, Qiu J, He M, Lu H B, Xing J, Zhou Y L
and Yang G Z 2007 Appl. Phys. Lett. 91 252110

[17] Lu H B, Jin K J, Huang Y H, He M, Zhao K, Cheng B L, Chen
Z H, Zhou Y L, Dai S Y and Yang G Z 2005 Appl. Phys. Lett.
86 241915

[18] Xiang W F, Lu H B, Chen Z H, Lu X B, He M, Tian H, Zhou Y
L, Li C R and Ma X L 2004 J. Crystal Growth 271 165

[19] Ahn C H, Bhattacharya A, Ventra M D, Eckstein J N,
Frisbie C D, Gershenson M E, Goldman A M, Inoue I H, Mannhart J,
Millis A J, Morpurgo A F, Natelson D and Triscone J M 2006 Rev.
Mod. Phys. 78 1185

[20] Shibuya K, Ohnishi T, Uozumi T, Sato T, Lippmaa M,
Kawasaki M, Nakajima K, Chikyow T and Koinuma H 2006 Appl.
Phys. Lett. 88 212116

[21] Pan F, Olaya D, Price J C and Rogers C T 2004 Appl.
Phys. Lett. 84 1573

[22] Ueno K, Inoue I H, Yamada T, Akoh H, Tokura Y and Takagi
H 2004 Appl. Phys. Lett. 84 3726

[23] Ueno K, Inoue I H, Akoh H, Kawasaki M, Tokura Y and
Takagi H 2003 Appl. Phys. Lett. 83 1755