Spin transistor using tunneling barrier

使用隧道势垒的自旋晶体管

基本信息

批准号：
14205056
负责人：
IWATA Satoshi
金额：
$ 31.2万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14205056/
关键词：
Magnetic random access memory Spin tunneling effect Spin dependent conduction Nano magnet Exchange Anisotropy Antiferromagnet Thermomagnetic writing Amorphous alloy 磁気固体メモリ反強磁性膜ナノ構造ブロッキング温度

项目摘要

Spin tunneling devices were fabricated by the magnetron sputtering system with 5 targets, where the metal masks for forming the electrodes were changed in vacuum system. Magnetoresistance(MR) ratio increased from few % to over 20% and the reproductivity of tunneling junction was improved by changing the magnetic layers from polycrystalline NiFe to amorphous CoFeB layer. This is due to improvement of the flatness of interface because of the structure without polycrystalline grains. Oxidization process of Al layer were investigated by dc plasma and rf plasma discharge in pure oxygen. In case of dc plasma, the tunneling devices exhibit large MR ratio with spin valve type MR curves in the range of the Al thickness between 1.3 nm and 1.6 nm and MR ratio shows maximum value of 30% at 1.4 nm. The dispersion of MR ratio between seven samples prepared at same process becomes very small. In case of rf plasma, although the MR ratio is 15% at Al thickness of 1.6nm, it decreases with decreasing Al thickness and becomes less than 1% at 1.3 nm. The dispersion of MR ratio between samples is larger than that for dc plasma case. These results show that the dc plasma is more suitable for oxidization of Al layer compared with rf plasma. However, the MR ratio for dc plasma case decreases more steeply with increasing voltage bias compared with rf plasma case, which implies that the oxidization process by dc plasma also should be improved. It is considered that these results are due to the deference in the degree of oxidization of Al layer and interface roughness of tunneling barrier. The tunneling devises show good thermal stability, where MR ratio does not change below 300 C annealing in the vacuum.

旋转隧道设备是由具有5个目标的磁控溅射系统制造的，其中用于形成电极的金属面具在真空系统中更换了。磁势（MR）比率从几％增加到20％以上，并且通过将磁性层从多晶纳夫（Polycrystalline Nife）更改为无定形的COFEB层来提高隧道连接的生殖力。这是由于没有多晶晶粒的结构，界面的平坦度提高了。通过DC血浆和RF血浆排放研究Al层的氧化过程。在DC血浆的情况下，隧道设备在1.3 nm和1.6 nm之间的自旋阀型MR曲线显示出较大的MR比率，而MR比率显示出1.4 nm时的最大值为30％。在同一过程中制备的七个样本之间的MR比分散非常小。在RF血浆的情况下，尽管MR比为15％的Al厚度为1.6nm，但它会随着Al厚度的降低而降低，并且在1.3 nm时的厚度小于1％。样品之间MR比的分散比DC血浆情况大。这些结果表明，与RF血浆相比，DC血浆更适合Al层的氧化。但是，与RF血浆病例相比，DC血浆病例的MR比随着电压偏置的增加而陡峭降低，这意味着DC血浆的氧化过程也应得到改善。据认为，这些结果是由于对Al层氧化程度和隧道屏障的界面粗糙度的尊重所致。隧道设计表现出良好的热稳定性，其中MR比在真空中不会变化以下300 c退火。

项目成果

期刊论文数量（15）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Uncompensated spins in a micro-patterned CoFeB/MnIr exchange bias system

微图案 CoFeB/MnIr 交换偏置系统中的未补偿自旋

DOI：
发表时间：
2004
期刊：
Appl. Phys. Lett. 85-12
影响因子：
0
作者：
Jong-Ho Park;Mitsuhiko Mase;Shoji Kawahito;Masaaki Sasaki;Yasuo Wakamori;Yukihiro Ohta;T.Eimuller et al.
通讯作者：
T.Eimuller et al.

STM observation and magnetic anisotropy of MBE-Grown Fe/Pt superlattices with (111) and (001) orientations

(111) 和 (001) 取向 MBE 生长的 Fe/Pt 超晶格的 STM 观察和磁各向异性