Abstract We study the efficiency of the magnetoimpedance (MI) of thin-walled circumferentially-ordered nanotubes in sub-GHz and GHz frequency regimes, using micromagnetic simulations. We consider empty ferromagnetic tubes as well as tubes filled with non-magnetic conductors of circular cross-section (nanowire coverings), focusing on the low-field regime of MI (below a characteristic field of the low-frequency ferromagnetic resonance). In this field area, the efficient mechanism of MI is related to oscillations of the positions of (perpendicular to the tube axis) domain walls (DWs). Two mechanisms of driving the DW motion with the AC current are taken into account; the driving via the Oersted field and via the spin-transfer torque. The simulations are performed for Co nanotubes of the diameter of 300 nm. Achievable low-field MI exceeds 100%, while the field region of a high sensitivity of that DW-based giant MI is of the width of tens of kA/m. The later is widely adjustable with changing the density of the driving AC current, its frequency, and the nanotube length. Of particular interest is the resonant motion of DW due to the interaction with the nanotube ends, the conditions of whom are discussed.

中文翻译：

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薄壁铁磁纳米管的畴壁辅助巨磁阻抗

摘要 我们使用微磁模拟研究了亚 GHz 和 GHz 频率范围内薄壁周向有序纳米管的磁阻抗 (MI) 效率。我们考虑空的铁磁管以及填充有圆形横截面的非磁性导体（纳米线覆盖物）的管，重点关注 MI 的低场区（低于低频铁磁共振的特征场）。在该场区域中，MI 的有效机制与（垂直于管轴）畴壁 (DW) 位置的振荡有关。考虑了用交流电流驱动 DW 运动的两种机制；通过奥斯特场和自旋转移矩驱动。对直径为 300 nm 的 Co 纳米管进行模拟。可实现的低场 MI 超过 100%，而基于 DW 的巨型 MI 的高灵敏度场区宽度为数十 kA/m。后者可以通过改变驱动交流电流的密度、频率和纳米管长度进行广泛调整。特别令人感兴趣的是 DW 由于与纳米管末端的相互作用而产生的共振运动，讨论了它们的条件。