TRANSPORT PHENOMENA OF SPIN-POLARIZED ELECTRON IN DOUBLE-TUNNELING BARRIER

双隧道势垒中自旋极化电子的输运现象

基本信息

批准号：
11450120
负责人：
TSUNASHIMA Shigeru
金额：
$ 9.92万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Exchange anisotropy has been investigated by torque magnetometory for MnPt (30 nm)/NiFe (5 nm) bilayers grown by the MBE method on MgO(001), SrTiO_3(001), and MgO(111) substrates. In-situ reflection high-energy electron diffraction observation and ex-situ X-ray diffraction measurements revealed that the MnPt layers have chemical order and have (100) uncompensated and (111) compensated plane parallel to the film plane, respectively for (001) and (111) substrate orientation. In PtMn/NiFe/SrTiO_3(001) unidirectional and uniaxial anisotropies have been observed, while in NiFe/PtMn/MgO(001) both the anisotropies almost disappeared and an anisotropy with four fold symmetry was observed. This anisotropy is thought to be closely related with the crystal anisotropy of PtMn.We have prepared NiFe/NiO bilayers and the NiFe/NiO/CoPt with various NiO thicknesses by RF magnetron sputtering under a dc magnetic field of 70 Oe, and investigated the magnetization process of these samples. In the NiFe/NiO bilayers, the exchange coupling field H_<ex> increased with increasing NiO thickness for t_<NiO>>10 nm, and becomes almost constant value of 110 Oe for t_<NiO>>20 nm. In the NiFe/NiO/CoPt trilayer, it is found that the magnetic moment of NiFe tend to align in the same direction as that of hard magnetic CoPt from the minor loop of the trilayer with NiO thickness of 10 nm. The loop shift depending on the direction of the CoPt moment did not appeared in the trilayer with the NiO thickness of 30 nm. The direction of the loop shift of NiFe layer was found to be controlled by changing of the direction of the applied field during the deposition.

MNPT（30 nm）/Nife（5 nm）双层通过MGO（001），SRTIO_3（001）和MGO（111）底物生长的MNPT（30 nm）/Nife（5 nm）双层对交换各向异性进行了研究。原位反射高能电子衍射观察和Ex-Situ X射线衍射测量表明，MNPT层具有化学阶，并且（100）无偿，并且（111）平行于膜平面，用于（001）（111）底物方向。在PTMN/NIFE/SRTIO_3（001）中，已经观察到单向和单轴各向异性，而在Nife/Ptmn/Mgo（001）中，各向异性几乎消失了，并且观察到了四倍对称性的各向异性。人们认为，这种各向异性与PTMN的晶体各向异性密切相关。我们已经准备好了Nife/Nio Bilayers和Nife/Nio/Nio/Copt，在70 OE的DC磁场下通过RF Magnetron溅射具有各种NiO厚度，并研究了磁化。这些样品的过程。在Nife/Nio BiLayers中，交换耦合场H_ <ex>随着T_ <nio >> 10 nm的NIO厚度的增加而增加，并且对于T_ <nio >> 20 nm而言，几乎变为110 OE的恒定值。在Nife/Nio/Copt Trilayer中，发现Nife的磁矩倾向于从三层的小环中与硬磁COPT相同的方向对齐，而NIO厚度为10 nm。循环移动取决于COPT矩的方向，并未出现在NIO厚度为30 nm的三层中。发现Nife层的回路移位方向通过在沉积过程中更改所施加场的方向来控制。