本文選題：熔體抽拉 + 非晶微絲��； 參考：《哈爾濱工業(yè)大學(xué)》2015年博士論文

【摘要】：本文分別從應(yīng)力作用、電化學(xué)方式處理、直流焦耳熱與梯度退火、液態(tài)介質(zhì)焦耳退火、直流與拋光復(fù)合式退火處理對微絲進行磁疇結(jié)構(gòu)調(diào)制,并系統(tǒng)研究了磁疇結(jié)構(gòu)與巨磁阻抗(GMI)效應(yīng)對應(yīng)關(guān)系,由此探討兩者的相關(guān)性。拉伸應(yīng)力可有效的改善微絲周向疇結(jié)構(gòu),使周向各向異性場變大。拉伸應(yīng)力203.7MPa時,阻抗達到最大比值[?Z/Z]max(%)=223.6%,相對制備態(tài)時提高了22.7%;扭轉(zhuǎn)應(yīng)力產(chǎn)生扭矩,感生螺旋各向異性,其周向分量有助于周向各項異性場、疇結(jié)構(gòu)的改善與周向磁導(dǎo)率的提高,有助于GMI的改善;頻率在f=15MHz、扭轉(zhuǎn)應(yīng)變?=20.4(2?rad/m)時,[?Z/Z%]max(%)達到最大值194.4%;磁疇變?yōu)椤癦字型”彎曲疇;平均疇尺寸1.1?m。電鍍能改變微絲表面磁各向異性,從而對GMI性能產(chǎn)生影響。等間距環(huán)向電鍍Ni(鍍層寬度2mm)3節(jié)后?Z/Zmax(%)=251.1%,比制備態(tài)高出40.4%;電鍍后,微絲未鍍區(qū)域周向疇的疇壁更清晰,平均疇尺寸0.73?m;Ni鍍層厚度約3?m,迷宮狀疇與整體疇取向周向分布;螺旋微電鍍Ni時,當(dāng)螺旋間距為50~200?m,?Z/Zmax(%)比值相對制備態(tài)有所提高;Ni層疇呈迷宮狀疇分布,疇壁不清晰;微絲表面周向疇分布明顯,平均疇尺寸為0.83?m。采用階梯式焦耳熱退火處理后,阻抗制備態(tài)比值?Z/Zmax(%)=469.6%;在階梯式80m A退火后,交流頻率f=7.4MHz,獲得了更高的GMI比值:?Z/Zmax(%)=654.1%(H0Oe);?Z/Zmax(%)=650.2%(H0Oe)。100m A階梯式焦耳退火后的?Z/Zmax(%)比值仍然很高,達到了631.9%(H0Oe)與624.6%(H0Oe),具有較大的響應(yīng)量程-1.5~0Oe/0~1.5Oe;對應(yīng)的場響應(yīng)靈敏度分別為:?=401.0%/Oe與?=397.5%/Oe。退火后,疇結(jié)構(gòu)得到改善,100m A階梯式電流退火后磁疇平滑且周向疇分布增多,交錯疇出現(xiàn),平均疇寬度增至0.98?m。由于GMI性能源于微絲的趨膚效應(yīng),通過在液氮中焦耳熱退火,加大退火電流到300m A電流幅值后,實現(xiàn)了微絲“芯部”晶化,而表面“殼層”仍為非晶態(tài)的“芯—殼”微結(jié)構(gòu)。這種結(jié)構(gòu)源于液氮低溫作用避免微絲殼層晶化,此時殼層厚度約為100nm。在頻率為8.1MHz時,GMI比值達到425%;外場在2.5~6.5Oe區(qū)間,響應(yīng)靈敏度達到99.4%/Oe;200m A電流幅值退火后,頻率在4~12MHz之間,GMI曲線呈現(xiàn)出0~6Oe的單調(diào)遞增響應(yīng)與10~80Oe的嚴(yán)格線性響應(yīng);后者較大的線性響應(yīng)特性,可用于檢測生物磁傳感器與探測理療產(chǎn)品的漏磁場;由此也驗證了微絲GMI性能取決于表面性能。當(dāng)采用300m A電流幅值退火后,由MFM獲得表面為周向與迷宮狀組成的復(fù)合疇結(jié)構(gòu),周向疇明顯改善,有序度提高,清晰的周向疇平均寬度為0.76?m。分析了Co基非晶微絲磁疇結(jié)構(gòu)的形成機理,并探明了熔體抽拉Co-Fe基非晶微絲的磁疇結(jié)構(gòu),提出了熔體抽拉Co-Fe基非晶微絲具有高的GMI比值與響應(yīng)靈敏度的磁疇結(jié)構(gòu)的三個特征:(a)單一周向疇,疇反向交替,規(guī)則分布;無雜散疇與“毛刺”現(xiàn)象;(b)周向疇界清晰且圓整,疇寬度均勻,尺寸約為1?m;(c)疇壁為180°Bloch壁,疇壁清晰,周向完整,疇壁平均寬度約10nm;無疇壁釘扎現(xiàn)象。
[Abstract]:In this paper, the magnetic domain structure is modulated from the stress action, the electrochemical treatment, the DC Joule heat and the gradient annealing, the Joule annealing of the liquid medium, the direct current and the polished annealing treatment. The correlation between the magnetic domain structure and the giant magnetic impedance (GMI) effect is studied systematically, and the correlation between the two is discussed. The tensile stress can be effective. In order to improve the circumferential domain structure, the circumferential anisotropy field becomes larger. When the tensile stress is 203.7MPa, the maximum ratio [? Z/Z]max (%) =223.6%) increases by 22.7% relative to the preparation state; torsional stress produces torque, and the spiral anisotropy is generated, and its circumferential component is helpful to the circumferential heterosexual fields, the improvement of the domain structure and the peri permeability. Improvement is helpful to the improvement of GMI; when the frequency is f=15MHz, the torsional strain? =20.4 (2? Rad/m), [? Z/Z%]max (%)] reaches the maximum value of 194.4%; the magnetic domain becomes the "Z type" curved domain; the average domain size 1.1? M. electroplating can change the magnetic anisotropy of the microfilament surface, thus affecting the GMI performance. The equidistance ring to the electroplating Ni (2mm) 3 of electroplating (2mm) 3? Z/Zmax (%) =251.1% is 40.4% higher than that of preparation state; after electroplating, the domain wall of the circumferential domain is clearer and the average domain size is 0.73? M; the thickness of the Ni coating is about 3? M, the labyrinth domain and the whole domain orientation are circumferential; when the spiral microelectroplating Ni, the ratio of the spiral spacing to 50~200? M, Z/Zmax (%) is relative to the prepared state; the Ni layer domain is labyrinth domain distribution. The wall is not clear; the surface of the microfilament is obviously distributed on the surface, and the average domain size is 0.83? M. using the step Joule annealing treatment. The impedance prepared state ratio? Z/Zmax (%) =469.6%; after the step 80m A annealing, the AC frequency f=7.4MHz is obtained. The higher GMI ratio is obtained: Z/ Zmax (%) =654.1% (H0Oe); Z/Zmax (%) Z/Zmax (%) stepped Joule retreat. The ratio of Z/Zmax (%) after fire is still high, reaching 631.9% (H0Oe) and 624.6% (H0Oe) and having a larger response range -1.5~0Oe/0~1.5Oe. The corresponding field response sensitivity is: after annealing of =401.0%/Oe and =397.5%/Oe., the domain structure is improved, and the 100m A step type current is smooth and the distribution of the peripheral domain is increased after the 100m A ladder type current annealing, and the interlaced domains appear. The average domain width increased to 0.98? M., due to the skin effect of GMI energy in microfilament, through the Joule heat annealing in liquid nitrogen, increasing the annealing current to the 300m A current amplitude, the "core" crystallization of the microfilament was realized, while the surface "shell" was still a amorphous "core shell" microstructure. This structure was derived from the effect of liquid nitrogen at low temperature to avoid microfilament shell. Layer crystallization, when the shell thickness is about 100nm. at 8.1MHz, the GMI ratio reaches 425%; the external field is in the 2.5~6.5Oe interval, the response sensitivity is 99.4%/Oe; after the 200m A current amplitude is annealed, the frequency is between 4~12MHz and the GMI curve shows the strict linear response of 0~6Oe and the 10~ 80Oe; the latter has a larger linear response characteristic, It can be used to detect the leakage magnetic field of the biological magnetic sensor and the detection of the physiotherapy products. It is also proved that the performance of the microfilament GMI depends on the surface performance. When the 300m A current amplitude is annealed, the composite domain structure with the circumferential direction and the labyrinth shape is obtained by the MFM. The circumferential domain is obviously improved, the order degree is improved, and the clear circumferential domain average width is 0.76? M. analyzed the formation mechanism of the magnetic domain structure of Co base amorphous microfilament, and explored the magnetic domain structure of melt pulling Co-Fe base amorphous microfilament, and proposed three characteristics of magnetic domain structure with high GMI ratio and response sensitivity of melt pulling Co-Fe base amorphous microfilaments: (a) single week domain, domain reverse alternation, regular distribution; no stray domain and "burr" "The phenomenon; (b) circumference is clear and round, the domain width is uniform, the size is about 1? M; the (c) domain wall is 180 degree Bloch wall, the domain wall is clear, the circumferential direction is complete, the domain wall average width is about 10nm; no domain wall pinning phenomenon.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TB303

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