Cell-scale micro-magnetic stimulation is the process of stimulating neuronal tissues using a sub-millimeter coil. During the process, a time-varying current is fed to the micro-coil, and the micro-coil generates a dispersed magnetic field in the focal region of the tissue to create the effect of magnetic stimulation. The micro-magnetic coil has the drawbacks of small inductance, large power consumption, low-quality factor, and uneven distribution of magnetic induction. In this article, we designed an improved F/C structure, which was surrounded by a magnetic film/planar coil, and developed a method for determining the geometric parameters of the structure based on an investigation of how the pattern, thickness, spacing, and width of the magnetic shielding layer (MSL) affect the micro-coil inductance LL and the magnetic induction BB . The experimental results show: when the magnetic permeability μr\mu _{r} of the micro-magnetic coil with the improved F/C structure is 106 H/m, the inductance reaches 1149.3 nH, the maximum value of magnetic induction BB on the Z=800Z = 800 nm tangential surface reaches 11.33 mT, and the average value of BB is 5.5 mT (the BB value exceeds 4.28 mT in 92.6% of the area of the 100μm×100μm100\,\,\mu \text{m}\,\,\times 100\,\,\mu \text{m} micro-coil); the range of action of magnetic induction is approximately 20 μm20~\mu \text{m} in the ZZ -direction. It can be concluded that the micro-magnetic coil with the improved F/C structure is superior to the existing micro-coils in terms of magnetic field uniformity, action strength, and inductance value, and the increased inductance value improves the quality factor QQ of the coil and reduces the power consumption of the micro-magnetic coil.

中文翻译：

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细胞级微磁线圈的改进F/C结构


细胞级微磁刺激是使用亚毫米线圈刺激神经元组织的过程。在此过程中，向微线圈馈入时变电流，微线圈在组织的聚焦区域产生分散磁场，从而产生磁刺激的效果。微磁线圈存在电感小、功耗大、品质因数低、磁感应强度分布不均匀等缺点。在本文中，我们设计了一种改进的 F/C 结构，该结构被磁性薄膜/平面线圈包围，并基于对图案、厚度、间距和形状的研究，开发了一种确定结构几何参数的方法。磁屏蔽层（MSL）的宽度影响微线圈电感LL 和磁感应强度BB 。实验结果表明：当改进F/C结构的微磁线圈的磁导率μr\mu_{r}为106 H/m时，电感达到1149.3 nH，磁感应强度BB达到最大值。 Z=800Z = 800 nm切面达到11.33 mT，BB平均值为5.5 mT（100μm×100μm100\,\,\mu \text{m}的92.6%面积BB值超过4.28 mT \,\,\times 100\,\,\mu \text{m}微线圈);磁感应强度的作用范围在ZZ方向上约为20 μm20~\mu \text{m}。由此可见，改进F/C结构的微磁线圈在磁场均匀性、作用强度、电感值等方面均优于现有微线圈，且增加的电感值提高了品质因数QQ。线圈并降低了微磁线圈的功耗。