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Developmental Research of Ferromagnetic Thin Films for Surface Acoustic Wave with Field-Induced Giant Attenuation

场致巨衰减声表面波铁磁薄膜的研究进展

基本信息

批准号：
62850130
负责人：
FUJIMORI Hiroyasu
金额：
$ 3.9万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-62850130/
关键词：
Surface Acoustic Wave Field-induced attenuation effect in SAW device SAW device Sputtered multi-layered thin film Ferromagnetic amorphous thin film ac magnetic susceptibility hysteresis loop Coercive force スパッター法金属膜作製交流帯確率多層確性膜

项目摘要

SAW delay line with evaporated nickel films shows an attenuation peak in a magnetic field parallel to the film plane which strongly depends on film thickness and magnetic fields. The maximum attenuation induced by fields was found to become about 40 dB/cm at 20 Oe (= H_c) for 200 A^^ﾟ thick Ni film. In order to get a SAW device having much larger attenuation effect, we have prepared the SAW devices with multi-layered Ni/W films. It was found that the field-induced attenuation was enhanced in proportion to the number of Ni layers. These results indicate that a SAW device with multi-layered Ni/W films gives a very large attenuation which can not be obtained with the single layered Ni film.In this term of project(1989), we firstly tried to get the SAW device which can control the attenuation by a small bias magnetic field. We have prepared amorphous thin films of (Fe_<1-x>Co_x)_<85>Zr_<15> on the substrates of Foto-ceram and quartz by ac plasma sputtering and studied the hysteresis loop and the field dependence of ac susceptibility. When the amorphous films are made by sputtering under an argon gas atmosphere with pressure less than 1 X 10^<-3> Torr, the films were found to have coercive force less than 1 Oe, at which the ac susceptibility shows a very large peak compared with that of a single layered Ni film. Then we have got one of the most suitable films for the SAW device which will show very large field-induced attenuation by a small magnetic field.Secondly, we designed the new SAW device made of lithium tantalate (LiTaO_3) with larger electromechanical coupling factor than that of crystalline quartz. We prepared the four kinds of SAW devices of 10 mm x 5 mm dimension which can generate SAW of 200, 500, 700 and 900 MHz,' respectively (the SAW devices were offered by the good offices of FUJITSU LIMITED). Testings of the above SAW devices with amorphous (Fe_<1-x>Co_x)_<85>Zr_<15> films are now in progress.

蒸镀镍膜的SAW延迟线在平行于膜面的磁场中出现一个衰减峰，该衰减峰强烈地依赖于膜厚和磁场。对于200A·ﾟ厚的Ni膜，在20Oe(=H_c)时，场致衰减的最大值约为40dB/cm。为了获得具有更大衰减效应的声表面波器件，我们制备了具有多层Ni/W薄膜的声表面波器件。结果表明，随镍层数的增加，场致衰减增强。这些结果表明，具有多层Ni/W薄膜的SAW器件具有很大的衰减，这是单层Ni薄膜所不能达到的。在本项目(1989)期间，我们首先尝试获得可以通过小偏置磁场来控制衰减的SAW器件。我们用交流等离子体溅射方法在FOTO-Ceram和石英衬底上制备了(Fe_&lt；1-x&gt；Co_x)_t；85&gt；Zr_&lt；15&gt；非晶薄膜，并研究了其磁滞回线和交流磁化率与磁场的关系。在气压小于1×10~(-3)Torr的Ar气氛下溅射制备的非晶态薄膜的矫顽力小于1Oe，其交流磁化率比单层Ni薄膜的磁化率有一个很大的峰值。其次，我们设计了一种新型的由钽酸锂(LiTaO_3)制成的SAW器件，其机电耦合系数比晶体石英的大。我们制备了4种尺寸为10 mm×5 mm的声表面波器件，分别可产生200、500、700和900 MHz的声表面波(声表面波器件由富士通公司的斡旋机构提供)。上述(Fe_&lt；1-x&gt；Co_x)_&lt；85&gt；Zr_&lt；15&gt；薄膜SAW器件的测试正在进行中。