以微型鎳柱磁導引結構實現異向性磁阻感測器於出平面磁場量測性能提升

Performance Enhancement of Out-of-Plane field measurements by anisotropic magneto-resistive sensor using micro-nickel-pillar flux guide structure

劉宗翰(Zong-Han Liu)

指導教授 ： 方維倫

國立清華大學/工學院/動力機械工程學系/碩士(2021年)

摘要

本研究藉由柱狀磁導引結構用以增強磁組感測器之出平面方向感測能力。當柱狀磁導引結構整合於異向性磁阻旁時，會因為鎳柱底端磁力線發散的特性，可以成功導引出平面的磁力線於同平面。因此，本研究提出新型香菇頭形狀鎳柱的磁導引結構，進一步增加出平面磁場的吸收量，進而增大轉移到異向性磁阻的磁通量，使其提高出平面靈敏度。本文提出新型香菇頭形狀磁導引結構整合於異向性磁阻旁的磁感測元件，並對異向性磁阻元件、整合柱狀結構於異向性磁阻以及整合香菇頭結構於異向性磁阻等三種不同元件，進行電阻變化率對同平面磁場和出平面磁場的比較。三者對於出平面方向磁場量測，在磁場強度140Gauss以前，所得的電阻變化率分別為0.06%、0.02%以及0.008%。同時，量測同平面的難軸的磁場，在磁場強度30Gauss以前，三者的電阻變化率分別為0.15%、0.13%以及0.1%。使用香菇頭形狀作為磁導引結構之元件與不具備磁導引結構的異向性磁阻，在出平面方向與同平面方向分別有7.5倍與1.3倍的靈敏度提升。

關鍵字

異向性磁阻 ； 磁導引結構 ； 出平面磁場

並列摘要

This study use Ni pillar structure to integrated beside the anisotropic magnetoresistance (AMR) which can successfully guide the out-of-plane flux into in-plane sensing direction, because of the divergence of the bottom of pillar. This study proposed the novel mushroom-shaped nickel pillar structure as flux guide to enhance the collecting ability of flux, at the same time, enhance the amount of flux transferring to the AMR, and improve the out-of-plane field sensitivity. Novel mushroom-shaped flux guide structure integrated with AMR sensor has been proposed in this thesis, and finish measurements, compared to the reference type of nickel pillar integrated with AMR and pure AMR on the out-of-plane and in-plane magnetic field versus normalized resistance change (Rx-Ro)/Ro . According to out-of-plane field measurements, before the magnetic field 140Gauss, the normalized resistance changes are 0.06%、0.02% and 0.008%. Meanwhile, the in-plane hard-axis direction magnetic field measurements, the normalized resistance changes are 0.15%、0.13% and 0.1% before magnetic field is 30 Gauss. Thus, the mushroom type flux guide integrated with AMR compared to the pure AMR structure has 7.5 fold sensitivity increments on the out-of-plane magnetic field sensing, and on the in-plane direction sensing, has 1.3 fold sensitivity improvements.

並列關鍵字

AMR ； magnetic flux guide ； out-of-plane magnetic field

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