Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, China.
Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physical Science and Engineering, Tongji University, Shanghai 200092, China.
Sci Rep. 2014 Feb 18;4:4117. doi: 10.1038/srep04117.
Combined methods of first-principles calculations and Landau-Lifshitz-Gilbert (LLG) macrospin simulations are performed to investigate the coherent magnetization switching in the MgO/FePt/Pt(001)-based magnetic tunnel junctions triggered by short pulses of electric field through the control of magnetic anisotropy energy (MAE) electrically. First-principles calculations indicate that the MAE of MgO/FePt/Pt(001) film varies linearly with the change of the electric field, whereas the LLG simulations show that the change in MAE by electric field pulses could induce the in-plane magnetization reversal of the free layer by tuning the pulse parameters. We find that there exist a critical pulse width τmin to switch the in-plane magnetization, and this τmin deceases with the increasing pulse amplitude E0. Besides, the magnetization orientation cannot be switched when the pulse width exceeds a critical value τmax, and τmax increases asymptotically with E0. In addition, there exist some irregular switching areas at short pulse width due to the high precessional frequency under small initial angle. Finally, a successive magnetization switching can be achieved by a series of electric field pulses.
采用第一性原理计算和朗道-利夫希茨-吉尔伯特（LLG）宏观自旋模拟相结合的方法，研究了通过控制磁各向异性能（MAE）电输运短脉冲电场触发 MgO/FePt/Pt(001)基磁隧道结中的相干磁化反转。第一性原理计算表明，MgO/FePt/Pt(001)薄膜的 MAE 随电场的变化呈线性变化，而 LLG 模拟表明，通过调节脉冲参数，MAE 的电场脉冲变化可以诱导自由层的面内磁化反转。我们发现存在一个临界脉冲宽度 τmin 来切换面内磁化，并且这个 τmin 随着脉冲幅度 E0 的增加而减小。此外，当脉冲宽度超过临界值 τmax 时，磁化方向不能被切换，并且 τmax 随着 E0 的增加而渐近增加。此外，由于初始角度较小，在短脉冲宽度下存在一些不规则的切换区域，因为其具有高进动频率。最后，可以通过一系列电场脉冲实现连续的磁化切换。
