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arXiv 1503.04560cond-mat.mtrl-sci
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横向磁场影响下电流和场驱动畴壁运动的动力学

Dynamics of Current and Field Driven Domain Wall Motion under the Influence of Transverse Magnetic Field

R. Arun, P. Sabareesan, M. Daniel

摘要:

采用Landau-Lifshitz-Gilbert(LLG)方程,结合绝热和非绝热自旋转移矩,对驱动场、电流和横向磁场共同作用下铁磁纳米带中横向Neel畴壁的动力学行为进行了解析和数值研究.采用小角度近似和Walkers试探函数,得到了畴壁速度、畴壁宽度、激励角和位移的解析表达式。结果表明,绝热自旋转移力矩可以控制畴壁的初始速度,而非绝热自旋转移力矩和驱动场可以控制畴壁的饱和速度。由于横向磁场的存在,在电流和磁场的驱动下,磁畴壁的饱和速度大大增加。横向磁场电流驱动的磁畴壁的饱和速度没有影响。对于在横向磁场存在下由电流驱动的畴壁,饱和速度保持恒定。横向磁场与电流和驱动场共同作用比横向磁场与电流共同作用更有利于提高磁畴壁的饱和速度。数值结果表明,横向磁场使饱和速度增大,且与驱动场和电流方向无关,当驱动场和电流方向分别为反平行和平行时,饱和速度更高,而当驱动场和电流方向分别为平行时,饱和速度更低。所得解析解与数值计算结果吻合较好。

英文摘要:

The dynamics of transverse Neel domain wall in a ferromagnetic nanostrip in the presence of driving field, current and transverse magnetic field is investigated by the Landau-Lifshitz-Gilbert(LLG) equation with the adiabatic and non-adiabatic spin-transfer torques both analytically and numerically. The analytical expressions for the velocity, width, excitation angle and displacement for the domain wall are obtained by using small angle approximation along with Walkers trial function. The results show that the initial velocity of the domain wall can be controlled by the adiabatic spin-transfer torque and the saturated velocity can be controlled by the non-adiabatic spin-transfer torque and driving field. The large increase in the saturated velocity of the domain wall driven by current and field due to the transverse magnetic field is identified through the presence of driving field. There is no impact in the saturated velocity of the domain wall driven by current from the transverse magnetic field. For the domain wall driven by the current in the presence of the transverse magnetic field, the saturated velocity remains constant. The transverse magnetic field along with current and driving field is more advantageous that the transverse magnetic field along with current for increasing the saturated velocity of the domain wall. The numerical results showed that the saturated velocity is increased by the transverse magnetic field with the irrespective of the directions of the driving field and current further it is higher and lower when the directions of driving field and current are antiparallel and parallel respectively. The obtained analytical solutions are closely coincided with the computed numerical results.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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