content_image/409474.jpg
<img src='content_image/409474.jpg'>

Support from CONICET (grants PIP 5254/05 and PIP 112-200801-00047) and ANCTyP (grants PICT 483/06 

1 G.I. Meijer, Science 319 , 1625 (2008). 2 

R. Waser and M. Aono, Nature Materials 6 , 833 (2007). 3 

A. Sawa, Materials Today 11 , 28 (2008). 4 

M. Janousch, G.I. Meijer, U. Staub, B. Delley, S.F. Karg, and B. P. Andreasson, Adv. Mat. 19 , 2232 (2007). 5 

K. Szot, W. Speier, G. Bihlmayer, and R. Waser, Nature Materials 5 , 312 (2006). 6 

I.H. Inoue, S. Yasuda, H. Akinaga, and H. Takagi, Phys. Rev. B 77 , 035105 (2008). 7 

K. Fujiwara, T. Nemoto, M.J. Rozenberg, Y., and H. Tak- agi, Jpn. J. App.Phys 47 , 6266 (2008). 8 

I.G. Baek, M.S. Lee, S. Seo, M.J. Lee, D.H. Seo, D.-S. Suh, J.C. Park, S.O. Park, H.S. Kim, I.K. Yoo, U.-In Chung, and J.T. Moon, Tech. Dig. IEDM. 587 (2004). 9 

S.Q. Liu, N.J. Wu, and A. Ignatiev, Appl. Phys. Lett. 76 2749 (2000). 

## ACKNOWLEDGMENTS 

and PICT 837/07) is gratefully acknowledged. 

10 A. Beck, J.G. Bednorz, Ch. Gerber, C. Rossel, and D. Widmer, App. Phys. Lett. 77 , 139 (2000). 11 

Y. Watanabe, J.G. Bednorz, A. Bietsch, Ch. Gerber, D. Widmer, A. Beck, and S.J. Wind, App. Phys. Lett. 78 , 3738 (2001). 12 

B.J. Choi, D.S. Jeong, S.K. Kim, C. Rohde, S. Choi, J.H. Oh, H.J. Kim, C.S. Hwanga, K. Szot, R. Waser, B. Re- ichenberg, and S. Tiedke, J. Appl. Phys. 98 , 033715 (2005). 13 

A. Baikalov, Y.Q. Wang, B. Shen, B. Lorenz, S. Tsui, Y.Y. Sun, Y.Y. Xue, and C.W. Chu, Appl. Phys. Lett. 83 957 (2003). 14 

Y.B. Nian, J. Strozier, N.J. Wu, X. Chen, and A. Ignatiev, Phys. Rev. Lett. 98 , 146403 (2007). 15 

N.A. Tulina, S.A. Zver’kov, Y.M. Mukovskii and D.A. Shulyatev, Europhys. Lett. 56 , 836 (2001). N.A. Tulina, Physics-Uspekhi 50 , 1171 (2007). 

