Development of magnetization reversal technique at low power consumption using a stress-induced magnetic anisotropy for perpendicular MRAM

利用垂直 MRAM 的应力感应磁各向异性开发低功耗磁化反转技术

• 批准号: 17360137
• 负责人: NAKAGAWA Shigeki
• 金额: $ 9.98万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360137/
• 关键词: Magnetic Random Access Memory; MRAM; Perpendicular MRAM; Inverse magneto-strictive effect; Stress-induced magnetization reversal; Anomalous Hall effect; DyFeCo; Perpendicularly magnetized films; データストレージ; 垂直磁化MRAM; 磁化反転; 応力誘起磁気異方性; スピンエレクトロニクス

Thin films with perpendicular magnetic anisotropy have a potential to achieve high-density cell arrangements as a perpendicular magnetic random access memory (p-MRAM). We have demonstrated a new method to reduce perpendicular coercivity of DyFeCo films using a stress-induced magnetic anisotropy. An isotropic stress applied to in-plane direction of the film was so effective to cause reduction of perpendicular magnetic anisotropy during the writing process if the film has large magnetostriction constant. In this study, we have succeeded to cause magnetization reversal at low magnetic field as low as 1/6 of original coercivity of the film. Magnetization processes of the films were measured using anomalous Hall effects and in-plane stress to the films was induced by a mechanical indentation method. It is observed that about 500 Oe of magnetic field in the reverse direction is enough to reverse completely the magnetization of the film which has an original coercivity of 3.3 kOe if the in-plane stress is applied to the film. This technique is applicable to the writing process of p-MRAM with wide writing margin at low power consumption.

具有垂直磁各向异性的薄膜作为垂直磁随机存取存储器（p-MRAM）具有实现高密度单元排列的潜力。我们展示了一种利用应力诱导磁各向异性来降低DyFeCo薄膜垂直矫顽力的新方法。当薄膜具有较大的磁致伸缩常数时，施加在薄膜平面内的各向同性应力可以有效地降低写入过程中垂直磁各向异性。在本研究中，我们成功地在低磁场下使薄膜的磁化反转，磁场低至原矫顽力的1/6。利用反常霍尔效应测量了薄膜的磁化过程，并利用机械压痕法诱导薄膜的面内应力。观察到，如果对薄膜施加面内应力，约500 Oe的反方向磁场足以完全逆转其初始矫顽力为3.3 Oe的磁化。该技术适用于低功耗、宽写入余量的p-MRAM的写入过程。

项目成果

An approach to estimate the magnetic anisotropy constants in a CoCrPt recording layer with NiFe soft underlayer

一种估计具有 NiFe 软底层的 CoCrPt 记录层磁各向异性常数的方法

• 发表时间: 2005
• 期刊: Journal of Magnetism and Magnetic Materials Vol.287
• 作者: S.Das;S.Nakagawa
• 通讯作者: S.Nakagawa

Evaluation of magnetization behavior of Soft/RE-TM layer for perpendicular MRAM by anomalous Hall effect

通过反常霍尔效应评估垂直 MRAM Soft/RE-TM 层的磁化行为

• 发表时间: 2007
• 期刊: Journal of Magnetism and Magnetic Materials 310・2
• 作者: Tomoya Hatori;Shigeki Nakagawa
• 通讯作者: Shigeki Nakagawa

Fabrication of CoCrPt-SiO_2 films on flexible tape substrate using facing target sputtering system

利用面向靶溅射系统在柔性带基材料上制备CoCrPt-SiO_2薄膜

• 发表时间: 2007
• 期刊: Journal of Magnetism and Magnetic Materials 310・2
• 作者: H.Fujiura;S.Nakagawa
• 通讯作者: S.Nakagawa

Magnetization reversal technique of DyTbFeCo films at magnetic field as low as 1/6 of coercivity using a stress-induced magnetic anisotropy

使用应力诱导磁各向异性在低至 1/6 矫顽力的磁场下 DyTbFeCo 薄膜的磁化反转技术

• 发表时间: 2007
• 期刊: IEEE Trans, on Magn. 43・6
• 作者: Michiya Yamada;Shigeki Nakagawa
• 通讯作者: Shigeki Nakagawa

BST(Ba0.5Sr0.5TiO3) Thin Films Prepared at Low Sputtering Gas Pressure by RF-Facing Targets Sputtering

低溅射气压下面向射频靶材溅射制备BST(Ba0.5Sr0.5TiO3)薄膜

• 发表时间: 2006
• 期刊: 14th Annual International Conference on Composites/Nano Engineering (ICCE-14)(Proceedings of ICCE-14) 2c
• 作者: Kazuhiro TAMAI;Mitsuru Nagasawa;Koji Nomura;Yuji Murashima Shigeki Nakagawa
• 通讯作者: Yuji Murashima Shigeki Nakagawa