Development of hightly oriented and low noise barium ferrite thin film media for high density magnetic recording

用于高密度磁记录的高取向、低噪声钡铁氧体薄膜介质的开发

• 批准号: 06650374
• 负责人: HOSHI Yoichi
• 金额: $ 1.34万
• 依托单位: Tokyo Institute of Polytechnics
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650374/
• 关键词: barium ferrite thin film; alternate periodic layr deposition method; facing target sputtering; magnetic recording medium; ZnO under layr; hexagonal ferrite; 薄膜; バリウムフェライト薄膜; スパッタ; ZnO薄膜; 対向ターゲット式スパッタ; 磁気的相互作用

Hexagonal barium ferrite (BaM : BaFe_<12>O_<19>) thin films are promising high density magnetic recording media, because they have not only excellent magnetic properties (large magnetic anisotropy energy) but also good mechanical and chemical stability. And because BaM is an oxide, the exchange interaction between the crystallites is easily reduced, which is necessary for a low-noise recording media. In this research, we attempted to obtain the BaM thin film with excellent c-axis orientation at a low substrate temperature by alternate periodic deposition of an S layr (spinel Fe_3O_4) layr) and an R (BaO・3Fe_2O_3) layr. Control of crystallite size in the BaM film was also attempted.(1) Control of crystallite size in the filmThe crystallite size in the BaM film decreased monotonically with decreasing film thickness, reaching a value below 30 nm in films 30 nm thick. Further decreases in film thickness led to a degradation of the crystallinity of the film, causing the saturation magnetiza … More tion and coercive force of the film to decrease significantly. A ZnO underlayr promoted the growth of c-axis-oriented hexagonal BaM crystallites in the film, but was not effective in reducing the crystallite size of the film. Furthermore, diffusion of Zn atoms from the underlayr to BaM film caused a decrease in the coercive force and saturation magnetization of the film. Growth of BaM crystallites in films deposited on a SiO_2/Si substrate was significantly suppressed when the films were deposited on a thin initial layr deposited on a SiO_2/Si substrate was significantly suppressed when the films were deposited on a thin initial layr deposited beforehand under a substrate bias of-50V.(2) Deposition of BaM film by alternate layr deposition methodDeposition of c-axis perpendicularly oriented barium ferrite (BaM : BaFe_<12>O_<19> thin films was attempted by means of an alternate periodic deposition of S (spinel Fe_3O_4 and R (BaO・3Fe_2O_3) layrs. The period of the layrs was fixed at 1.15 nm, which corresponds to the period of hexagonal barium ferrite crystals in the c-axis direction. The films deposited at temperatures above 540ﾟC had a hexagonal crystal structure and showed excellent c-axis orientation, but this deposition method did not results in a marked reduction of substrate temperature needed for the deposition of a BaM film with hexagonal crystal structure. The films deposited at 630ﾟC had a clear terraced surface due to the growth of disk shaped hexagonal crystallites. The saturation magnetization of the film was about 220 emu/cc and the coercive force of the films was about 2.2kOe. Less

六方钡铁氧体(BAM：BaFe)薄膜不仅具有优异的磁性能(大的磁各向异性能)，而且具有良好的机械和化学稳定性，是一种很有前途的高密度磁记录介质。由于BAM是氧化物，晶体之间的交换作用很容易降低，这是低噪声记录介质所必需的。在本研究中，我们试图通过交替沉积S层(尖晶石Fe_3O_4)层和R(BaO·3Fe_2O_3)层来在较低的衬底温度下获得具有良好c轴取向的BaM薄膜。(1)薄膜中微晶尺寸的控制BAM薄膜中的微晶尺寸随着薄膜厚度的减小而单调减小，在30 nm厚的薄膜中，微晶尺寸达到30 nm以下。薄膜厚度的进一步减小导致薄膜的结晶度降低，导致饱和磁化强度…薄膜的磁化强度和矫顽力明显降低。氧化锌衬底促进了薄膜中c轴取向的六方BAM微晶的生长，但不能有效地减小薄膜的微晶尺寸。此外，锌原子从衬底向BAM薄膜的扩散导致薄膜的矫顽力和饱和磁化强度降低。当薄膜沉积在SiO_2/Si衬底上时，BAM晶体的生长受到显著抑制。当薄膜沉积在SiO_2/Si衬底上时，薄膜的生长受到显著抑制。(2)交替分层沉积方法沉积BAM薄膜：垂直于c轴取向的BaAM铁氧体(BAM：BaFe_&lt；12-gt；O_&lt；19&gt；尝试了交替周期沉积S(尖晶石Fe_3O_4和R(BaO·3Fe_2O_3)层)薄膜的方法。层状结构的周期为1.15 nm，与六方晶系钡铁氧体晶体在c轴方向的周期相对应。在540ﾟC以上温度下沉积的薄膜具有良好的c轴择优取向，具有六方晶体结构，但这种沉积方法并没有显著降低沉积具有六方晶体结构的薄膜所需的衬底温度。在630ﾟC温度下沉积的薄膜具有清晰的梯形表面，这是由于盘状六方晶的生长。薄膜的饱和磁化强度约为220emu/cc，矫顽力约为2.2kOe。较少

项目成果

星陽一 他: "スパッタ法による超高硬度ダイヤモンドライクカーボン保護膜の作製" 日本応用磁気学会誌. 19,S2. 104-107 (1995)

Yoichi Hoshi等：“溅射法制备超硬类金刚石碳保护膜”日本应用磁学学会杂志19，S2 104-107（1995）。

星陽一 他: "スパッタ法による超高硬度ダイヤモンドライクカーボン保護膜の作製" 日本応用磁気学会誌. 19.S2. 104-107 (1995)

Yoichi Hoshi等人：“溅射法制备超硬类金刚石碳保护膜”日本应用磁学学会杂志19.S2 104-107（1995）。

Y. Hoshi et al.: "Suppression of cone formation on carbon target during sputtering" Jpn. J. Appl. Phys.33. 4991-4996 (1994)

Y. Hoshi 等人：“溅射过程中碳靶上锥体形成的抑制”Jpn。

Y. Hoshi et al.: "Uniaxial magnetetic anisotropy of iron thin films deposited by oblique incidence of deposition particles." J. Appl. Phys.(to be published). (1996)

Y. Hoshi 等人：“通过沉积颗粒倾斜入射沉积的铁薄膜的单轴磁各向异性。”

Y.Hoshi et al.: "Preparation of c-axis oriented barium ferrite thin films with small crystallite size" J.Appl.Phys. 80(掲載予定). (1997)

Y.Hoshi 等人：“小晶粒尺寸的 c 轴取向钡铁氧体薄膜的制备”J.Appl.Phys 80（待出版）。