巨磁电阻薄膜材料的研究进展

对巨磁电阻薄膜材料及其制备技术的发展现状进行了综述和评价,重点介绍了国内外在电沉积巨磁电阻薄膜材料方面的最新进展,并指出磁场对电沉积的影响是一个值得深入探讨的研究方向。     

金属磁性功能材料的最近进展

本文综述了若干新的金属及其他磁性功能材料的最近进展。这些材料包括巨磁电阻材料、高密度磁记录材料、纳米晶软磁材料、粘结Ｎｄ－Ｆｅ－Ｂ和Ｓｍ－Ｆｅ－Ｎ永磁材料、金属原子簇磁性材料和含Ｂｉ石榴石型铁氧体磁光膜材料。     

2003-2004年金属磁性功能材料研究新进展

本综述性论文开始写于1995年,其后每年撰写.本年综述的内容包含：（1）巨磁致伸缩材料;（2）巨磁电阻材料;（3）垂直磁记录材料;（4）石榴石型铁氧体磁光材料;（5）Sm-Co系稀土合金的结构和磁性.     

退火温度对Co-Ag颗粒膜结构及巨磁电阻效应的影响

采用磁控溅射方法在室温衬底上制备了Co30Ag70(原子百分比)颗粒膜。利用X射线衍射谱(XRD)和四探针方法研究了Co30Ag70颗粒膜沉积态及真空退火后的室温结构和室温巨磁电阻效应。结果表明：沉积态颗粒膜织构较明显，巨磁电阻效应呈现各向异性；随着退火温度的升高，Co30Ag70颗粒膜的微结构发生了演变，导致Co30Ag70颗粒膜的巨磁电阻效应呈现先降后升再降的现象，在473K达到最大值，其值约为-5．7％。     

磁场下电沉积制备CuCo颗粒膜的巨磁电阻效应

在磁场下电沉积制备CuCo功能膜材料,研究膜层的巨磁电阻效应及磁性能.应用X射线衍射仪(XRD)对镀层微观结构随热处理温度的变化进行分析,采用四引线法及振动样品磁强计(VSM)测量膜层的磁性能.磁阻测试发现:磁感应强度为0.6 T下制备的CuCo颗粒膜经500 ℃真空退火处理1 h后,其巨磁电阻值较无磁场下制备的提高约25%,这是由于0.6 T下制备的颗粒膜晶粒较致密,同时磁场减少了膜层内部缺陷,如杂质、夹杂等.样品磁滞回线表明:500 ℃真空退火处理1 h后膜层具有最佳的磁性能,此时膜层中的单磁畴磁性粒子有助于提高巨磁电阻值.CuCo颗粒膜电沉积制备过程中施加磁场可以改善膜层的微观结构,使其具有更高的巨磁电阻效应.     

全球新型材料发展前沿概览

2009年度材料科技的进展 材料科技的进展成为人类进步的强大“引擎”。《今日材料》2007年在评价材料科学时,将国际半导体技术蓝图、扫描式探针显微镜、巨磁电阻效应、半导体激光器和发光二极管、美国国家纳米技术计划、碳纤维复合材料、锂离子电池材料、碳纳米管、     

2003-2004年磁性功能材料及应用研究新进展

本综述性论文开始写于1996年，其后每年撰写。本年综述的内容包含：（1）磁性超薄膜；（2）巨磁电阻材料；（3）磁显微术及其应用；（4）软磁铁氧体材料；（5）磁流体材料。     

关于钛的回顾与评价（Ⅱ）

综述了１９９４～１９９５年间若干磁性功能材料研究及应用的进展，包括Ｆｅ—Ｎ系高磁矩材料，自旋阀巨磁电阻材料，Ｓｍ２Ｆｅ（１７）Ｘｙ系新稀土永磁材料，磁浮列车新设计，高梯度磁分离技术应用和ＹＩＧ微波铁氧体应用。     

玻璃包覆钴基非晶细丝的巨磁阻抗研究

深入研究了玻璃包覆的成分为Ｆｅ６８．２５Ｃｏ４．５Ｓｉ１２．２５Ｂ１５,直径为２５ｕｍ的非晶细丝的巨磁阻抗效应。在频率为０．１～１２ＭＨｚ,磁场在０～５．２ｋＡ／ｍ的范围内测量了交流磁电阻、磁电抗、磁阻抗对频率及磁场的依赖关系。发现该细丝材料的巨磁阻抗ＧＭＩ（Ｚ）值在测量频率范围内随频率增大而增大。     

Co-Fe-Ni-Nb-Si-B非晶软磁合金薄带巨磁阻抗效应

研究了Ｃｏ－Ｆｅ－Ｎｉ－Ｎｂ－Ｓｉ－Ｂ非晶软磁合金薄带的磁性和巨磁阻抗（ＧＭＩ）效应。样品在３５０℃下退火６０ｍｉｎ后获得了最佳的软磁特性,并表现出优良的ＧＭＩ效应。在１．４ＭＨｚ的交变电流频率下,获得了最大的ＧＭＩ效应,磁阻抗比ΔＺ／ＺＳ＝（Ｚ０－ＺＳ）／ＺＳ最高可达１９２％。在低频下得到了显著的巨磁电感效应,在１００ｋＨｚ下,磁电感比达到７６９％。在高频下,材料表现出优良的巨磁电阻效应,在１３     

Spin valves based on amorphous ferrimagnetic Gd–Co films

Multilayer Gd–Co/Co/Cu/Co structures were prepared by magnetron sputtering. An analysis of the magnetic and resistive properties allows us to classify these structures among spin valves which demonstrate the giant magnetoresistance effect. The mechanism of the sign reversal of giant magnetoresistance with changing thickness of the Co layer, which is exchange coupled with the ferrimagnetic Gd–Co layer, has been interpreted.     

Layered magnetic structures in research and application

An overview is given on the status of research and applications in the field of layered magnetic structures and the historical development is indicated. Currently the research on interlayer exchange coupling, giant magnetoresistance and tunnel magnetoresistance is particularly active, therefore the basic understanding of these phenomena, the size of the effects, important issues and applications are discussed in some more detail.     

A new single bath for the electrodeposition of NiFe/Cu multilayers exhibiting giant magnetoresistance behavior

A new single bath for the electrodeposition of ultrathin NiFe/Cu multilayers was developed and magnetoresistance measurements were conducted. Complementary methods such as scanning electron microscopy (SEM), x-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the multilayers. Magnetoresistance measurements indicated that the multilayers grown from this new bath exhibited a giant magnetoresistance (GMR) behavior.     

时效工艺对Cu-Co-Ni合金的磁学性能和GMR效应的影响

对时效过程中Cu80Co15Ni5合金的磁学性能和巨磁电阻效应（GMR）的变化规律进行了试验研究。通过理论计算了合金中磁性颗粒的尺寸、数量等微结构参数随时效工艺的变化以及其对GMR效应的影响规律，并进一步研究了GMR效应随时效工艺变化的机理。     

Pr掺杂对(Fe_(100-x)Co_x)/Cu多层膜GMR及电磁性能的影响

采用直流磁控溅射法制备Pr_x(Fe_(100-x)Co_x)_(100-x)/Cu多层膜,X射线衍射实验结果表明,稀土元素Pr有促进FeCo、Cu的相分离的作用,热处理提高了薄膜的结晶度;巨磁电阻(GMR)效应测量结果表明,在同样的退火温度下,随着Pr掺杂含量的增加,薄膜的GMR值呈急速下降趋势;随着退火温度的升高,样品的巨磁电阻效应GMR呈现出先增后减小的趋势。随着退火温度的升高,样品的矫顽力随之升高,并可在在550℃时达到4.0437×10~4A/m。     

Magnetocaloric effect in Ni-Mn-<Emphasis Type="Italic">X</Emphasis> (<Emphasis Type="Italic">X</Emphasis> = Ga,In, Sn,Sb) Heusler alloys

A review is given of experimental and theoretical works concerning the investigation of magnetic and structural phase transitions and of the magnetocaloric effect in Ni-Mn-X (X = Ga, In, Sn, Sb) Heusler alloys possessing unique properties, such as the existence of coupled magnetostructural and metamagneto-structural phase transitions, giant magnetocaloric effect, shape-memory effect in the ferromagnetic state, giant magnetodeformation and magnetoresistance, exchange anisotropy. A conclusion is made that the Heusler alloys, because of their unique properties, are promising for the application in various engineering devices, including technology of magnetic refrigeration.     

Crystal structures and giant magnetoresistance of fluoride La2/3Ca1/3MnO3 compounds

The crystal structures and giant magnetoresistance of CaF₂-doped La_2/3Ca_1/3MnO₃ compounds are investigated by means of X-ray powder diffraction (XRD) and magnetic measurements. The Rietveld powder diffraction profile fitting technique is employed to refine the crystal structures. The results indicate that the space group of all these compounds is Pbnm, with Z=4. In each unit cell, the 4a, 4c, 4c, and 8d crystal positions are occupied by Mn ions, La ions, O^I, and O^II anions, respectively. The F atoms substitute for the O atoms in the 8d crystal position. The Curie temperatures of these compounds are enhanced slightly by adding CaF₂, and the giant magnetoresistance (GMR) ratios are higher than 67.6% in an applied field of 5 T.     

Giant Magnetoresistance of Metallic Exchange-Coupled Multilayers and Spin Valves

The microstructure and the magnetic and magnetotransport properties have been investigated depending on the types of the magnetic and nonmagnetic materials, composition, nanostructure, and regimes of thermomagnetic treatments for two types of metallic nanostructures, namely, magnetic multilayers and spin valves, which exhibit the effect of a giant magnetoresistance (GMR). Magnetosensitive materials that are promising for the applications in microelectronics have been synthesized: CoFe/Cu multilayers with record values of the GMR effect (81%); NiFeCo/Cu multilayers with a sensitivity of 0.5%/Oe; and microobjects prepared on the basis of spin valves, which possess the anhysteretic field dependence of the magnetoresistance and a GMR effect equal to 9%. Special attention is given to the methods of decreasing hysteresis. A comparison of the obtained results with the results for similar types of materials published earlier has been carried out.     

相位相干与巨磁电阻极大值

用双流模型研究磁性金属－金属型颗粒膜（Ｆｅ－Ａｇ,Ｃｏ－Ａｇ）中巨磁电阻（ＧＭＲ）极大值特性,结果表明,磁性颗粒内杂质原子之间的相位相干,对磁电阻极大值的产生有重要影响,这种相位相干与外场磁化的综合作用使颗粒膜巨磁电阻的尺寸关系表现出非单调的特征,并用该模型计算和讨论了巨磁电阻的其它性质,结果与实验符合较好。     

Giant magnetoresistance and super-paramagnetism in electrodeposited NiFe/Cu multilayers

The giant magnetoresistance of electrodeposited NiFe/Cu multilayers from a single bath under potentiostatic control is studied. The observed nonsaturating behavior urged us to investigate the probability of the occurrence of superparamagnetic regions in these multilayers. In this research, for the first time, the presence of super-paramagnetic regions in electrodeposited NiFe/Cu multilayers is shown and proved via high resolution transmission electron microscopy. The reason was found to be the existence of a very large anodic transient at the beginning of the copper deposition pulse, which could be eliminated by choosing a more negative potential.