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APPLICATION OF SPIN-DEPENDENT TRANSPORT IN HYBRID SUPERLATTICE TO FUNCTIONAL DEVICES

混合超晶格中自旋相关输运在功能器件中的应用

基本信息

批准号：
10450139
负责人：
MATSUYAMA Kimihide
金额：
$ 5.76万
依托单位：
KYUSYU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

In this research project, magnetic and electric properties of semiconductive-oxide (TiOx and SnOx)/ferromagnet multilayers were investigated by magnetoresistance (MR) measurements in a CPP geometry. By using semiconducting materials as a non-magnetic separating layer of a CPP device, the junction resistance can be smaller than that of typical TMR devices consisting of Al_2O_3 layer. It is considered that the lowering of the junction resistance in a CPP device is much important for the application of a readout. head of a hard disk. The prepared multilayers consisting of subst./CoPt (10 nm)/Co (2 nm)/SC (t nm)/Co (4 nm)/SC (t)/Co (2 nm)/CoPt (10 nm) where SC=TiOx or SnOx, t=4, 8 nm. These multilayers were prepared by rf- and dc-magnetron sputtering on a glass substrate at nominal temperature and patterned into CPP device structure by photo-lithography and Ar ion milling.The active area for the CPP transport was 5 μm×5 μm. From the magnetoresistance (MR) measurements of these samples, it … More was found that the MR ratio for the TiOx-based multilayer (0.1 % at 77 K) was much smaller than that for the SnOx-based one (2.0 % at 77 K). Furthermore, the MR profile of the TiOx-based multilarer was totally different from another one in the saturation behavior. The large saturation field observed in the MR curve of the TiOx-based multilayer was an order of larger than that for the MH curve measured with VSM.This indicates that the CPP transport property is dominated by the super-paramagnetic behavior of the Co cluster due to the interlayer atom diffusion between Co and TiOx layers. This interlayer diffusion of Co atoms into TiOx layer would suppress the MR ratio of the TiOx-based multilayer. This super-paramagnetic behavior was not observed in the MR curve of SnOx-based multilayer. This suggests that the diffusion of the ferromagnetic Co atoms into semiconductive-oxide layer was restrained by using SnOx. The MR ratio was decreased from 2.1 % to 1.0 % as increasing the SnOx layer thickness from 4 nm to 8 nm. It is considered that the decrease is caused by the scattering of the spin-polarized electron in SnOx layer. Less

在本研究项目中，通过在CPP几何结构中的磁电阻（MR）测量，研究了半导体氧化物（TiOx和SnOx）/铁磁体多层膜的磁性和电学性质。采用半导体材料作为CPP器件的非磁分离层，可以使器件的结电阻小于典型的Al_2O_3层TMR器件的结电阻。认为降低CPP器件的结电阻对读出器件的应用具有重要意义。硬盘的头。制备的多层膜由subst./CoPt (10 nm)/Co (2 nm)/SC (t nm)/Co (4 nm)/SC (t)/Co (2 nm)/CoPt （10 nm）组成，其中SC=TiOx或SnOx， t= 4,8 nm。这些多层膜是在标称温度下通过射频和直流磁控溅射在玻璃衬底上制备的，并通过光刻和氩离子铣削加工成CPP器件结构。CPP输运的活跃区域为5 μm×5 μm。从这些样品的磁阻（MR）测量中发现，tiox基多层膜的磁阻比（77 K时为0.1%）远小于snox基多层膜的磁阻比（77 K时为2.0%）。此外，tiox基倍增器的磁共振谱在饱和行为上与其他倍增器完全不同。在tiox基多层膜的MR曲线上观察到的大饱和场比用VSM测量的MH曲线大一个数量级。这表明，由于Co和TiOx层之间的层间原子扩散，Co团簇的超顺磁性行为主导了CPP的输运性质。Co原子向TiOx层的层间扩散会抑制TiOx基多层膜的MR比。这种超顺磁行为在snox基多层膜的MR曲线上没有观察到。这表明SnOx抑制了铁磁性Co原子向半导体氧化层的扩散。随着SnOx层厚度从4 nm增加到8 nm，磁流变率从2.1%下降到1.0%。认为这是由于自旋极化电子在SnOx层中的散射引起的。少