Study on spin-valve type multi-value memory using spin glass/ferromagnetic exchange coupled thin film

自旋玻璃/铁磁交换耦合薄膜自旋阀型多值存储器的研究

• 批准号: 10650017
• 负责人: SATO Tetsuya
• 金额: $ 2.18万
• 依托单位: Keio University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650017/
• 关键词: Spin glass; Spin valve; exchange coupled thin film; Multi-value memory; Magneto-resistance; 磁性多層膜; 交換結合; 磁気異方性

Magnetic anisotropy and the magnetic phase transition temperature in reentrant spin glass NiMn/Cu multilayer and NiMn/Cu/Ni trilayer films were investigated to fabricate a spin valve type memory. For the trilayer film, the field dependent magneto-resistance was measured to discuss the possible contribution from the giant magneto-resistance (GMR) effect.NiMn/Cu multilayer and NiMn/Cu/Ni trilayer film were prepared using the Ar ion-beam sputtering method in an ultra high vacuum chamber. The magnetic anisotropy was estimated using a superconducting quantum interference device (SQUID) magnetometer.The magnetic phase transition temperatures decrease with decreasing the film thickness in NiMn/Cu multilayer sample. When the sample was annealed, however, the ferromagnetic phase transition temperature increased. This indicates that the ferromagnetic magnetization of the annealed NiMn sample is maintained up to a higher temperature compared with the non-annealed sample. In addition, the magnetic anisotropy field was analyzed as a function of the thickness of the Cu layer in the trilayer sample. As a result, we found that a magnetic coupling between NiMn and Ni layers becomes pronounced when the thickness of Cu layer is thinner than a thickness between 30 and 59 AィイD4゜ィエD4. This is an important information to fabricate the GMR trilayer film in which the decoupling between the magnetic layers is required. The GMR effect could not be confined because the contribution from the anisotropic magneto resistance is significant in the trilayer sample, due to the small difference of the resistance among the three layers.

研究了重入自旋玻璃NiMn/Cu多层膜和NiMn/Cu/Ni三层膜的磁各向异性和磁相变温度。采用Ar离子束溅射法在超高真空室中制备了NiMn/Cu多层膜和NiMn/Cu/Ni三层膜，测量了薄膜的场相关磁电阻，讨论了巨磁电阻效应对薄膜磁电阻的影响。用超导量子干涉仪（SQUID）测量了NiMn/Cu多层膜样品的磁各向异性，结果表明，随着膜厚的减小，NiMn/Cu多层膜样品的磁相变温度降低。然而，当样品退火时，铁磁相变温度升高。这表明，退火的NiMn样品的铁磁磁化强度与未退火的样品相比保持到更高的温度。此外，磁各向异性场作为一个功能的三层样品中的铜层的厚度进行了分析。结果，我们发现，当Cu层的厚度比30和59埃之间的厚度薄时，NiMn和Ni层之间的磁耦合变得显著。这对于制备需要磁层间去耦的GMR三层膜是一个重要的信息。由于三层样品中各向异性磁电阻的贡献很大，因此GMR效应不能被限制，因为三层样品中三层之间的电阻差异很小。

项目成果

H. Kawai and T. Sato: "Magnetic response of Cd0.63Mn0.37Te under illumination: Dynamic behavior of spin glass with step-like heating and cooling"J. Appl. Phys.. 85. 7310-7315 (1999)

H. Kawai 和 T. Sato：“Cd0.63Mn0.37Te 在光照下的磁响应：阶梯式加热和冷却的旋转玻璃的动态行为”J。

T.Sato,M.Furusaka,M.Takeda: "Magnetization process of itinerant-electron-type helical-spin-glass reentrant magnet Cr0.81Mn0.19Ge observed on various spatial scales"J.Magn.Magn.Mater.. 195. 345-361 (1999)

T.Sato，M.Furusaka，M.Takeda：“在不同空间尺度上观察到的巡回电子型螺旋自旋玻璃重入磁体 Cr0.81Mn0.19Ge 的磁化过程”J.Magn.Magn.Mater.. 195。

H.Kawai,T.Sato: "Magnetic response of Cd0.63Mn0.37Te under illumination:Dynamic behavior of spin glass with step-like heating and cooling"J.Appl.Phys.. 85(10). 7310-7315 (1999)

H.Kawai,T.Sato：“Cd0.63Mn0.37Te 在光照下的磁响应：阶梯式加热和冷却的旋转玻璃的动态行为”J.Appl.Phys.. 85(10)。

T.Itoh and T.Sato: "Peculiar decay of thermoremanent magnetization observed in Fe doped Cd0.62Mn0.38Te"J.Magn.Soc.Japan. 23(1-2). 507-509 (1999)

T.Itoh 和 T.Sato：“在 Fe 掺杂 Cd0.62Mn0.38Te 中观察到的热剩磁的特殊衰减”J.Magn.Soc.Japan。

伊藤 巧: "Peculiar decay of thermoremanent magnetization observed in Fe doped Ca_<0.62>Mn_<0.38>Te" the Journal of the Magnetics Socrety of Japan. 23. 507-509 (1999)

Takumi Ito：“Fe 掺杂 Ca_<0.62>Mn_<0.38>Te 中观察到的热剩磁的特殊衰减”，日本磁学会杂志 23. 507-509 (1999)。