铁基巨磁阻抗薄膜的研究

溅射方法制备的非晶Ｆｅ６８Ｃｕ０．５Ｃｒ４Ｖ５Ｓｉ１３．５Ｂ９薄膜,通过适宜的退火处理得到具有纳米ａ－Ｆｅ（Ｓｉ）和非晶母相的混合结构和最佳的软磁性能,相应的巨磁阻抗值最高可达７２％。本着重研究了热处理条件、薄膜组织结构、较磁性能以及驱动电流频率对Ｆｅ６８Ｃｕ０．５Ｃｒ４Ｓｉ１３．５Ｂ９薄膜磁致阻抗的影响。     

Co—Fe—Si—B非晶丝的巨磁阻抗效应研究

用旋转水中纺丝法制成几种不同直径的（Ｃｏ０．９４Ｆｅ０．０６）７２．５Ｓｉ１２．５Ｂ１５非晶丝,对丝进行张力退火后,测试了非晶丝热处理前后的磁阻抗性能。结果表明制成的非晶丝具有明显的巨磁阻抗效应,且巨磁阻抗效应随电流频率不同而表现出正磁阻抗和负磁阻抗两种规律。张力退火对正磁阻抗效应有明显改善,而且对直径小的试样,阻抗对轴向外磁场变化的灵敏度更高。实验得到的最大灵敏度为１２４％／Ｏｅ。     

热处理对Fe_(79.5)P_(12)C_6Cu_(0.5)Mo_(0.5)Si_(1.5)软磁合金薄带的巨磁致阻抗效应(GMI)的影响

研究了不同温度热处理对Ｆｅ７９．５Ｐ１２Ｃ６Ｃｕ０．５Ｍｏ０．５Ｓｉ１．５的巨磁阻抗的影响，发现ＧＭＩ不仅与磁导率有关，而且也受到磁各向异性的作用。     

热处理对F79.5P12C6Cu0.5Mo0.5Si1.5软磁合金薄带的巨磁致阻抗效应

研究了不同温度热处理对Ｆｅ７９．５Ｐ１２Ｃ６Ｃｕ０．５Ｍｏ０．５Ｓｉ１．５的巨磁阻抗的影响，发现ＧＭＩ不仅与磁导率有关，而且也受到磁各向异性的作用。     

预退火对Fe73.5Cu1Mo3Si13.5B9纳米晶合金形成的影响

采用Ｘ射线衍射，电子衍射及透射电子显微技术研究了Ｆｅ７３．５Ｃｕ１－ｘＭｏ３Ｓｉ１３．５Ｂ９非晶合金４１０℃预退火对随后４８０℃退火所形成的纳米晶结构的影响。结果表明，预退火对Ｆｅ７３。０５，Ｃｕ１Ｍｏ３Ｓｉ１３．５Ｂ９合金纳米晶结构的形成有重要影响。当预退火时间从０小时增加到３小时，合金在４８０℃，小时退火形成的晶相化α－Ｆｅ（Ｓｉ）的晶粒尺寸从１５ｎｍ减小到８ｎｍ。预退火使α－Ｆｅ（Ｓｉ）相的     

Fe76.5—xCu1NbxSi13.5B9纳米晶合金的结构和磁性研究

本文研究了Ｆｅ７６．５－ｘＣｕ１ＮｂｘＳｉ１３．５Ｂ９纳米晶合金中Ｎｂ含量的变化（ｘ＝１－７）对结构和磁性的影响。结果表明，随ｘ值的增高，α－Ｆｅ（Ｓｉ）纳米晶相的尺寸减小，体积分数，含Ｓｉ量及其ＤＯ３有序度降低。Ｎｂ含量对残余非晶相的结构有影响。合金的饱和磁致伸缩系数（λｓ）随ｘ值的增加而增大，在ｘ＝３时，合金的起始磁导率（μｉ）最大，矫顽力（Ｈｃ）最小。     

Fe73.5Cu1Mo3Si13.5B9微晶软磁合金的结构及其对磁性的影响

对Ｆｅ７３．５Ｃｕ１Ｍｏ３Ｓｉ１３．５Ｂ９微晶软磁合金的结构及其对合金磁性的影响了研究，结果表明，在最佳磁性能下，晶相点阵常数ａ＝０．２８４３ｎｍ，相当于Ｆｅ（Ｓｉ）固溶体中含Ｓｉ％（ｍｏｌ／ｍｏｌ）：１８－２０，体积百分数Ｖ＝７４．８％，晶粒尺寸Ｄ＝１４．６ｎｍ；残余非晶层厚度δ＝１．２３ｎｍ；当Ｔ退火≥５６０℃时明显有Ｆｅ－Ｂ化合物析出。Ｆｅ７３．５Ｃｕ１Ｍｏ３Ｓｉ１３．５Ｂ９合金的磁性不仅与     

Fe_（76．5－x）Cu_1Nb_xSi_（13．5）B_9纳米晶合金的结构和磁性研究

本文研究了Ｆｅ（７６．５－ｘ）Ｃｕ１ＮｂｘＳｉ（１３．５）Ｂ９纳米晶合金中Ｎｂ含量的变化（ｘ＝１－７）对结构和磁性的影响。结果表明，随ｘ值的增高，α－Ｆｅ（Ｓｉ）纳米晶相的尺寸减小，体积分数，含Ｓｉ量及其ＤＯ_３有序度降低。Ｎｂ含量对残余非晶相的结构有影响。合金的饱和磁致伸缩系数（λｓ）随ｘ值的增加而增大，在ｘ＝３时，合金的起始磁导率（μｉ）最大，矫顽力（Ｈｃ）最小。     

机械球磨法制备纳米晶Fe_（73．5）Cu_1Nb_3Si_（13．5）B_9的

对Ｆｅ_（７３．５）Ｃｕ_１Ｎｂ_３Ｓｉ_（１３．５）Ｂ_９成分的母合金进行了机械球磨，并对不同时间的球磨样品进行了Ｘ射线衍射（ＸＲＤ）和Ｍｏｓｓｂａｕｅｒ谱（ＭＳ）的测量，结果表明样品难以完全非晶化，形成了无序的αＦｅ－Ｓｉ固溶体纳米晶，晶粒尺寸在５ｎｍ左右，同时共有一部分富集Ｎｂ，Ｂ元素的界面非晶相。在各种球磨条件下对αＦｅ－Ｓｉ固溶体中的Ｓｉ含量进行了计算。纳米晶Ｆｅ_（７３．５）Ｃｕ_１Ｎｂ_３Ｓｉ_（１３．５）Ｂ_９软磁合金近年来受到了广泛的重视~［１］。这种材料通常是由熔融金属急冷制成非晶薄带，然后在晶化温度以上退火制成，晶化以后在非晶基体上均匀析出１０－２０ｎｍ尺寸的αＦｅ－Ｓｉ固溶体。机械球磨或机械合金化是近些年来发展起来的一种制备亚稳态材料如非晶，纳米晶，准晶等的有效手段，有一定优越性。本文利用机械球磨探讨一种制备纳米晶Ｆｅ_（７３．５）Ｃｕ_１Ｎｂ_３Ｓｉ_（１３．５）Ｂ_９合金粉末的新途径。     

机械球磨法制备纳米晶Fe73.5Cu1Nb3Si13.5B95的结构研究

对Ｆｅ７３．５Ｃｕ１ｎｂ３Ｓｉ１３．５Ｂ９成分的母合金进行了机械球磨，并对不同时间的球磨样品进行了Ｘ射线衍射（ＸＲＤ）和Ｍｏｓｓｂａｕｅｒ谱（ＭＳ）的测量，结果表明样品难以完全非晶化，形成了无序的αＦｅ－Ｓｉ固溶体的纳米晶，晶粒尺寸在５ｎｍ左右，同时共存一部分富集Ｎｂ，Ｂ元素的界面非晶相。在各种球磨条件下对αＦｅ－Ｓｉ固溶体中的Ｓｉ含量进行了计算。     

应力作用下电流退火对钴基非晶薄带的巨磁阻抗效应的影响研究

采用应力作用下的直流电流退火处理Co68.2Fe2.3Mo2Si12.5B15非晶薄带，详细讨论了应力退火前后Co基薄带的巨磁阻抗效应的变化，以及退火时间对巨磁阻抗效应的影响，研究表明：应力作用下的电流退火有利于巨磁阻抗效应的提高，并可以通过控制退火时间控制阻抗与外场变化关系曲线形状。     

Giant Stress—impedance Effect in Amorphous and Current Annealed Fe73.5Cu1Nb3Si13.5B9 Ribbons

The giant stress-impedance(GSl) effect in amorphous and current annealed Fe73.5Cu1Nb3Si13.5B9 ribbons has been investigated .The results showed that the GSl effect changed drastically with annealing techniques and the maximum stress impedance ratio of 350% was obtained after optimal conditions of current annealing .The behaviors of the stress impedance vary with densities of annealing current and the stress longitudinally applied during current annealing.The maximum change of stress impedance existed in the sample annealed by high-current-density electropulsing under applied stress of 100MPa.     

Magneto-impedance element

The magneto-impedance (MI) effect is a phenomenon in which the voltage induced by a high frequency current source in a ferromagnetic wire changes with the application of an external field. A giant MI effect was found in amorphous magnetic wires having a composition of (Fe _0.06Co_0.94)_72.5Si_12.5B ₁₅ and a magnetostriction of (-10^-7). The amplitude of the wire voltage decreased by 40% at 1 MHz, 60% (600 kHz) and 50% (150 kHz), for wires having diameters 30 μm, 50 μm and 124 μm, respectively, under the influence of an external longitudinal field of about 10 Oe (800 A/m). A highly sensitive and quick-response field sensor was constructed using a 200 MHz resonant multivibrator bridge-circuit combining two MI-effect elements of 1 mm length with two field effect transistors (FET). Highly sensitive flux detection was carried out by using the small MI sensor head on a rotary encoder magnet having 512 poles and a diameter of 30 mm. Discussion of a mechanism for the MI effect considers the skin effect in an amorphous wire with high circumferential anisotropy     

Influence of AC magnetic field amplitude on the surface magnetoimpedance tensor in amorphous wire with helical magnetic anisotropy

We have performed experimental and theoretical studies on the influence of ac magnetic field amplitude on the magnetoimpedance tensor in an amorphous wire with helical magnetic anisotropy. For the experimental measurements, we used an amorphous wire of composition (Co/sub 0.94/Fe/sub 0.06/)/sub 72.5/Si/sub 12.5/B/sub 15/ with negative, nearly zero magnetostriction constant, excited either by an ac circular h/sub /spl phi// or by an axial h/sub z/ magnetic field created by an ac electric current. We changed the ac current amplitude from 7.5 to 40 mA and the current frequency f from 1.5 to 20 MHz. The values of the asymmetric giant magnetoimpedance ratio associated with the sweeping direction of the dc field H/sub ex/ and the corresponding sensitivity were 211% and 0.64 V/Oe, respectively, for an ac current of 37.5 mA at 3 MHz. For the theoretical study based on the magnetization rotation, we obtained the second-order harmonic of the ac magnetization m/spl I.oarr//sup (2)/ induced by the relatively high ac magnetic field by solving the Landau-Lifshitz-Gilbert (LLG) equation. We also considered a second-order surface impedance tensor /spl sigmav//spl circ//sup (2)/, which allowed us to analyze quantitatively the influence of the ac magnetic field amplitude on the impedance tensor of the wire. We obtained the domain model of the wire with helical magnetic anisotropy having multidomains and the magnetization vector /spl plusmn/M/sub 0/ directed in the easy direction, and the corresponding static magnetic configurations, by solving the static LLG equation. For the given magnetic configurations, we calculated the second-order impedance tensor /spl sigmav//spl circ//sup (2)/. The results can well explain the irregular field characteristics of the voltage responses at low dc field value, when the wire was excited at high frequency and at large ac magnetic field.     

非晶丝微磁化线圈磁电阻抗效应研究

本文研究了铁基及钴基非晶态合金丝在由微磁经线圈所产生的轴向交变磁场的作用下所呈现的磁电阻抗效应，经出了一些测试结果，结果表明，微磁化线圈两端的电压信号峰－峰值随轴向外磁场Ｈｅ的增加而单调减少，钴基非晶丝可呈现巨磁电阻抗效应，利用该效应可制成新型磁敏元件及器件。     

Microstructural and Microhardness Variation of Amorphous Fe78Si9B13 Alloy during Bend Stress Relaxation

The amorphous Fe78Si9B13 ribbons were bend stress relaxed at various temperature well below the crystallization temperature （Tx） for different time. The effect of pre-annealing on the subsequent bend stress relaxation was examined. The variation of the microstructure and microhardness during bend stress relaxation process was studied using X-ray diffraction （XRD）, atomic force microscopy （AFM） and Vickers microhardness test,respectively. Curvature radius of the amorphous Fe78Si9B13 ribbons decreased with increase bend stress relaxation temperature and time. The microhardness of the stress relaxed specimens increased with time at 300℃ due to the forming of nanocrystals during bend stress relaxation. The pre-annealing reduced the decrease rate of the curvature radius of stress relaxed specimens.     

Dependence of frequency and amplitude of the ac current on the GMI properties of Co based amorphous wires

The frequency and the amplitude of the driving ac current dependence of the Giant Magneto-Impedance (GMI) behaviour in (Fe₆Co₉₄)_72.5Si_12.5B₁₅ amorphous wire have been studied. The single and two-peak behaviour in the GMI characteristics are observed which depends on the amplitude and frequency of the ac driving current flowing through the sample. The GMI ratio initially increased and then decreased monotonically with the increase of frequency, f, and the amplitude of the ac current, I_ac. With the increase of amplitude of ac current, the response of the GMI voltage is found non-linear with the generation of higher harmonics. With the increase of higher harmonics, the first harmonic component of the GMI voltage started decreasing. With the increase of the ac current, the field sensitivity of the first harmonic components of the GMI voltage decreases and in higher harmonics it shows an increasing trend. The maximum field sensitivity was observed 7.5% per A/m for I_ac = 2 mA and at frequency 100 kHz. The paper investigates the response of the second and third harmonics with the frequencies and amplitude of the driving current. A voltage equation derived from the rotational model to study the response of the GMI voltage.     

铁钴镍基非晶态软磁材料的研究

研究了１０钟以铁钴镍为基的非昌态软磁材料，对非晶态合金的成分，熔点，晶化温度，居里温度及一些磁性能作了分析比较、将将材料制成元件装到电子镇流器上试验，研究结果表明，铁磁元素铁钴镍的含量比例，是影响非晶态磁性的主要因素；类金属元素对软磁材料的磁性能也有一定的影响，含磷的非晶态合金的熔点，晶化温度及居里温度比含碳的较高。     

Micromagnetic Structure of Co-Rich Amorphous Microwires

1. IntroductionSince the discovery of amorphous materials theirmagnetic prOPerties have been eXtensively studieddue to a great deal of laterest for fundamental investigations and their enormous potelltial in technological applications (in sensors, transducers, magnetic screens). Co-rich amorphous wires are promising candidates for a variety of sensor applications.It is knownlll thst some importal magnetic characteristics for technical applications (for example,low field magnetoresistance, mag…