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Controllable magnetic anisotropy (MA) by electricity is one of current targets in the technologies [1-8]. MA is an important magnetic properties and the understanding in the atomic scale could contribute a development of the high-density magnetic recording medium. Strong MA energy is required for small magnetic devices to keep their magnetization against the thermal disturbances and further, the system is also required to be able to afford the magnetization reversal by an assistance of electric field (EF). The experiences on these MAs could help us to understand the relationship between magnetic anisotropies and electronic structures, providing building blocks for the material design on MA. In the presentation, I would review results of theoretical calculations on magnetic anisotropy for metallic systems by some research groups [9-12] and discuss the electric filed effects on MA with presenting results of electronic structures. I would also discuss the Rashba effect on MA energy by using a simple example of magnetic surface [13]. [1] D. Chiba, et al., Nature, 455, 515 (2008). [2] M. Weisheit et al., Science, 315, 349 (2007). [3] T. Maruyama et al., Nature Nanotech. 4, 158 (2009). [4] Y. Shiota et al., Appl. Phys. Express 2, 063001 (2009). [5] T. Nozaki et al., Appl. Phys. Lett., 96, 022506 (2010). [6] M. Endo et al., Appl. Phys. Lett. 96, 212503 (2010). [7] F. Bornell et al., Appl. Phys. Lett., 98, 23251 (2011). [8] T. Seki et al., Appl. Phys. Lett., 98, 212505 (2011). [9] C. G. Duan, et al., Phys. Rev. Lett. 101, 137201 (2008). [10] K. Nakamura, et al., Phys. Rev. Lett. 102, 187201 (2009). [11] M. K. Niranjan et al., Appl. Phys. Lett. 96, 222504 (2010). [12] M. Tsujikawa and T. Oda, Phys. Rev. Lett., 102, 247203 (2009). [13] M. Tsujikawa and T. Oda, submitted for publication. |
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