以第一原理研究5d過渡金屬覆蓋層對磁性異向能的影響

The Effect of 5d Transition Metal Capped Layer on The Magnetic Anisotropy of Fe/MgO(001) Thin Films by First Principle.

陳宥成(You-Cheng Chen)

指導教授 ： 梁贊全

國立中正大學/理學院/物理學系/碩士(2014年)

摘要

本文以第一原理研究計算5d過渡金屬覆蓋層對生長在MgO(001)基板之鐵薄膜的磁性異向能之影響。我們會先討論鐵原子的層數對磁性異向能的效應，再探討氧化鎂基板對磁性異向能的影響，我們發現氧化鎂基板的存在會增強多層鐵薄膜的磁性異向能。之後研究5d過渡性金屬覆蓋層對Fe1(MgO)4的磁性異向能之效應，我們發現其中Os、Ir和Pt對Fe1(MgO)4磁性異向能影響最明顯。最後我們將針對這三種不同的5d過渡金屬覆蓋在Fe(MgO)4分析外加電場、外加應力、磁性層與過渡金屬覆蓋層之層數對磁性異向能的影響。M/ Fe(MgO)4的磁性異向能隨著鐵原子層數的增加也會有震盪的行為。外加應力對磁性異向能的影響比外加電場的影響來得大。而較大的垂直磁性異向能可以應用在高密度的儲存裝置上。

關鍵字

磁性異向能 ； 第一原理

並列摘要

In this thesis, the magnetic anisotropy energy (MAE) of Fe/MgO(001) thin films was investigated by the fist-principles calculation. We found that the MAE of Fe and Fe/MgO thin films oscillate in magnitude with the thickness of the magnetic films slab. The MAE of magnetic thin films was enhanced by presence of the MgO substrate. The capping 5d elements M (i.e., Os, Ir and Pt) on the magnetic thin film have significant effects on MAE. The MAE of M/Fe(MgO) oscillated with the thickness of the Fe slab. Moreover, the in-plane applied strain on the M/Fe(MgO) has more significant effect than those of an external electric field. The results of this study could be useful to the high density magnetic data storage.

並列關鍵字

magnetic anisotropy energy ； first principle

參考文獻

[4] P. Bruno, Phys. Rev. B 39, 865 (1988).

[5] G. Laany, J. Phy. Condens. Matter 10 3239-3253 (1998).

[8] G. H. O. Daalderop, Phys. Rev. B. 41, 11919 (1990).

[9] K. Nakamura, T. Akiyama, and T. Ito, Phys. Rev. B 81, 220409 (2010).

[10] G. Kresse, and J. Hafner, Phys. Rev. B 47, RC558 (1993)