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Development of super-laminated magneto-resistance materials of copper-cobalt using by electroplating and repeated rolling

电镀反复轧制超叠层铜钴磁阻材料的研制

基本信息

批准号：
09555228
负责人：
KUWAHARA Hideyuki
金额：
$ 7.36万
依托单位：
RESEARCH INSTITUTE FOR APPLIED SCIENCES
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

Giant magneto-resistant (abbreviated as GMR or MR) materials are prepared by such evaporation methods as sputtering or ion plating techniques.Electroplating or mechanical alloying method for preparing MR materials is also developed.In order to be able to easily prepare large size MR materials, various laminated materials that reveal GMR has been investigated in the present study by a new combination system of repeated rolling and heat treatment followed electroplating cobalt on copper.Cobalt was electroplated in the thickness from 1.7 to 50 mum on both sides of thin copper foil of 9 or 16 mum in thickness.Then they were joined with same size copper foil at 1173 K for 14.4 ks in a flowing hydrogen gas atmosphere (pressure : 66.7 Pa) followed stacking 24 to 400 layers alternatively copper foil coated with cobalt and pure copper cut to 10X45 mm^2 respectively.Joined samples were in the range of thickness from about 220 to 4500 mum.Such prepared samples were repeatedly rolled at room tempe … More rature to about 16 mum in thickness without annealing during rolling.Moreover, rolled material was cut to size of 10X45 mm^2, stacked, joined, and rolled.Finally, samples were gotten from 2000 layers to 41,000,000 layers in the thickness of 10 to 60 mum. These samples were heat-treated in the range of temperature from 573 to 873 K for 3.6 ks in the flowing hydrogen gas atmosphere (pressure : 66.7 Pa) and cooled to room temperature.Microstructure of these samples were observed using a scanning electron microscope and MR of all samples were measured at room temperature or at 77 K.The maximum MR of Cu-Co binary system in the present study shows about 24% at room temperature.Such big value of MR would be caused to small inter-spacing of dispersed Co particles in the matrix of Cu phase.The operation of quenching to room temperature followed joining at 1173 K formed supersaturated solid solution of Cu phase with dissolved cobalt.Moreover, repeated rolling at room temperature also made forcedly the supersaturated solid solution.The supersaturated cobalt was precipitated as fine dispersed particles in the Cu phase matrix by heat-treatment.Energy dispersed spectroscopy analysis on a cross section of a sample which 1.7 *m thickness of electroplated Co layer and 16 *m thickness Co foil were alternatively stacked to 399 layers showed l2at%Co and l5at%Co, respectively.The structure on the cross section of these samples was observed as lamella.MR ratio of 12at%Co-Cu was sensitively changed by reduction ratio, though it was slightly effected by heat treatment time.Almost 15at%Co-Cu showed higher MR ratio than that of 12at%Co-Cu.Large MR ratio would be revealed by a suitable laminated number and heat treatment rather than by laminated number.Only increasing laminated number would suppress refining Co particle size. Less

巨磁阻（简称GMR或MR）材料的制备方法有溅射法、离子镀法等蒸发法，也有电镀法、机械合金化法等制备MR材料的方法，为了能够方便地制备大尺寸MR材料，本研究通过一种新的反复轧制和热处理的组合系统，研究了显示巨磁电阻的各种层压材料在铜上电镀钴，在厚度为9或16 μ m的薄铜箔的两侧电镀厚度为1.7至50 μ m的钴，然后在流动的氢气气氛中在1173 K下将它们与相同尺寸的铜箔连接14.4 ks（压力：66.7 Pa），然后堆叠24至400层，或者涂覆有钴的铜箔和切割成10 × 45 mm的纯铜。2。连接的样品的厚度在约220至4500 μ m的范围内。将这样制备的样品在室温滕佩下反复轧制 ...更多信息在轧制过程中不进行退火，将其加热至约16 μ m厚。然后，将轧制材料切割至10 × 45 mm^2的尺寸，堆叠、连接并轧制。最后，获得厚度为10至60 μ m的2000层至41，000，000层的样品。这些样品在流动的氢气气氛中在573~873K的温度范围内热处理3.6ks（压力：使用扫描电子显微镜观察这些样品的显微结构，并在室温或77 K下测量所有样品的MR。本研究中的Co二元体系在室温下的MR值约为24%，如此大的MR值可能是由于Cu相基体中弥散分布的Co颗粒间距过小所致，淬火至室温后在1173 K下连接形成了溶解有Co的Cu相过饱和固溶体，室温下反复轧制也强制形成过饱和固溶体。通过热处理，过饱和钴在铜相基体中以细小分散颗粒的形式析出。对厚度为1.7 * m的电镀Co层和厚度为16 * m的Co箔交替堆叠399层的样品的横截面进行能量分散光谱分析，显示12at%Co和15at%Co，12at%Co-Cu合金的磁电阻率随还原率的变化很敏感，15at%Co-Cu合金的磁电阻率比12at%Co-Cu合金的磁电阻率高，但热处理时间对磁电阻率的影响不大。大的磁电阻率不是由层片数决定的，而是由合适的层片数和热处理决定的，只有增加层片数才能抑制Co颗粒的细化。少