Fabrication of Curie point written solid state magnetic memories

居里点写入固态磁存储器的制作

• 批准号: 13555092
• 负责人: TSUNASHIMA Shigeru
• 金额: $ 8.7万
• 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: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13555092/
• 关键词: solid state magnetic momery; MRAM; spin tunneling junction; non-volatile memory; Blocking temperature; exchanae anisotropy; spin polarized transport; solid state magnetic momery; MRAM; spin tunneling junction; non-volatile memory; Blocking temperature; exchanae anisotropy; spin polarized transport

Micropatterned amorphous films for thermomagnetic recording, TMR films using amorphous alloy layers, exchange biased films, and thermomagnetic recording process were investigated.(1) TbFe amorphous alloy films were prepared by rf magnetron sputtering, and microfabricated by focused ion beam (FIB) and conventional photolithography methods. Switching of the magnetization of TbFe elements was confirmed after current pulses which give rise to Joule heat in the elements. The current density necessary for the switching was found to decrease with decreasing the element size, and the 0.5μm squared element was found to be switched by applying the current density as small as 1.6 x 10^6 A/cm^2. In addition, tunnel junctions including TbFe amorphous alloy layer was found to exhibit sufficiently large magneto resistance ratio.(2) NiFe/Mnlr exchange biased films were microfabricated by FIB and their magnetic domain structures were observed by magnetic force microscopy (MFM). The easy direction of the NiFe/Mnlr elements lay in the film plane, and for such in-plane elements having 1 : 1 aspect ratio, it is difficult to obtain sigle domain state. Thus, the perpendicular magnetized elements such as TbFe were found to be effective to accomplish single domain state if the elements have 1 : 1 aspect ratio.(3) Simulation of thermomagnetic recording process was carried out, and the simulation was used to obtain material parameters which are necessary for recording of domains smaller than 100 nm. For the recording of domains smaller than 50 nm on an RE-rich TbFeCo medium, the increase of coercivity, which might be realized by controlling the microstructure of the TbFeCo film, was found to be needed.

研究了用于热磁性记录的微孔无形膜，使用无形合金层的TMR膜，交换偏置膜和热磁性记录过程。（1）TBFE无定形合金膜通过RF Magnetron溅射制备，由RF Magnetron溅射，并通过聚焦离子束（FIB）和征服性方法（FIB）和图片化方法。在当前脉冲引起元素中引起焦耳热的电流脉冲后，确认了TBFE元件的磁化化的切换。发现开关所需的电流密度随着元素尺寸的减小而减小，并且发现0.5μm平方元件通过施加电流密度小至1.6 x 10^6 a/cm^2进行切换。此外，发现隧道连接包括无定形合金层存在适当的大磁电阻率。（2）通过FIB将Nife/MNLR交换偏置膜微生物微生物，并且通过磁力显微镜（MFM）观察到其磁性结构结构。 Nife/MNLR元素的简单方向位于膜平面上，对于具有1：1纵横比的平面内元素，很难获得Sigle域状态。这是，如果元素具有1：1的纵横比，则发现垂直的磁化元素（例如TBFE）有效地完成单个域状态。（3）进行热磁记录过程的模拟，并使用模拟来获得材料参数，以获取用于记录域小于100 nm所必需的材料参数。对于在重新富含的TBFECO培养基上小于50 nm的域的记录，人们发现，可以通过控制TBFECO膜的微观结构来实现的矫正性增加。