應用於超高密度磁性記錄媒體之鈷基合金與複合式記錄媒體相關研究

簡易檢索 / 詳目顯示

回結果列表

研究生：	侯皓程 Hou, Hao-Cheng
論文名稱：	應用於超高密度磁性記錄媒體之鈷基合金與複合式記錄媒體相關研究 Co-based alloy and composite media for ultra-high density magnetic recording disk
指導教授：	賴志煌 Lai, Chih-Huang
口試委員:	林敏聰 Lin, Minn-Tsong 張慶瑞 Chang, Ching-Ray 金重勳 Chin, Tsung-Shune 林克偉 Lin, Ko-Wei
學位類別：	博士 Doctor
系所名稱：	工學院 - 材料科學工程學系 Materials Science and Engineering
論文出版年：	2012
畢業學年度：	100
語文別：	英文
論文頁數：	154
中文關鍵詞：	硬碟片、磁性記錄、磁性材料、濺鍍製程、同步輻射、磁性鑑定
外文關鍵詞：	hard disk drive, magnetic recording, magnetic material, sputter, synchrotron radiation, magnetometry measurement
相關次數：	點閱：2 下載：0
分享至:	分享至facebook 分享至twitter

查詢本校圖書館目錄查詢臺灣博碩士論文知識加值系統勘誤回報

由於具備高容量、低成本的特性，硬碟裝置被普遍使用在電腦裝置以及各式消費性電子產品中，做為大量儲存數位資訊的重要媒介。硬碟片技術開發，最關鍵的一環，在於如何將碟片記錄密度持續提升，使硬碟機容量滿足大量化資訊儲存的需求，因此，開發兆位元等級之超高密度碟片技術，是過去十年碟片製造商及全球磁性研究領域上一個重大的課題，亦是本論文的主要研究方向。
本論文針對超高密度碟片相關技術進行開發與深入研究，研究課題著重於鈷基合金及複合式記錄膜層。第一部分探討磁性記錄層的材料選擇對於磁性記錄層的特性影響。比較不同氧化物添加於鈷鉻鉑合金，我們發現薄膜微結構中，具較低化學穩定性的氧化物，呈現較佳的晶界偏析程度，且磁晶粒間的磁交互耦合力明顯下降。透過X光吸收術分析，推測低化學穩定性的氧化物，在濺鍍過程中，容易釋出多餘的氧氣，使其成為氧化劑，促使晶界上的鉻氧化，令晶界上產生氧化鉻偏析，達到較好的磁交互力阻絕特性。
本論文第二部分著重在開發複合式記錄膜層結構。我們提出新穎式[鈷鉻鉑-二氧化矽/鉑]多層狀軟磁層結構，可透過改變鉑的厚度，控制軟磁層的垂直磁異向性及層間磁交互作用力。利用此複合結構，可以將碟片的磁性寫入場有效降低，並且提升其熱穩定性。我們同時藉由同步輻射光源的X光磁圓偏振二向性量測術，觀察複合薄膜的硬軟磁性層的翻轉非同調性。在碟片讀寫測試中，相較於傳統單一膜層結構，我們發現此複合式媒體在訊雜比及覆寫能力上，具有明顯提升。
論文最後一部分探討複合式膜層結構的磁性翻轉機制及關鍵量測技術之建立。我們透過X光磁圓偏振二向性量測術及磁性標定參雜層，得到具縱深解析之磁矩特性，隨著軟磁層厚度增加，直接在實驗端觀察並驗證由同調翻轉變成磁區壁輔助磁翻轉的行為改變。另一部份，我們使用了極化中子反射術，直接觀察軟磁層厚度對層間交互耦合力的影響，解析得到交互耦合力在縱深方向的強度分布。

Hard disk drives (HDDs) play a key role in mass data storage techniques, which are widely used in computer systems and various consumer electronics owing to their ad-vantages of low cost and high capacity. The growing demand for the HDD capacity drives the researches in increasing the areal density of the recording disk. This dissertation focuses on three main research topics to reach ultra-high density recording disks.
The first topic investigates the Co-based alloy, which is currently used as the recording layer in commercial hard disks. By using first order reversal curves (FORCs), we found out distinct magnetization reversal behavior in the CoPtCr films with different oxide additives, including Ta2O5, SiO2 and their mixtures. Based on our results, increasing the Ta2O5-to-SiO2 ratio alters the inter-grain interaction from an exchange coupling (parallel) to a dipolar-field coupling (anti-parallel). During the sputtering process, the Ta2O5 additives release extra oxygen to induce the formation of CrOx. The reduced inter-grain exchange coupling strength by increasing Ta2O5 additives can be attributed to the increased volume concentration of oxides and/or the presence of the CrOx.
The second topic aims at developing the advanced layer structure of composite media (or called exchange coupled composite (ECC) media) comprising magnetically hard and soft layers. We proposed a soft layer with a laminated structure (LSL, [Pt/CoPtCr-SiO2]5), which uniquely exhibits a tunable perpendicular anisotropy by modifying the Pt thickness. The incoherent reversal in the composite media with a LSL was directly observed by using X-ray magnetic circular dichroism (XMCD). With increasing Pt thickness, the anisotropy of LSL is reduced, which promotes the incoherent reversal of composite media to lower its switching field; however, further increasing the Pt thickness significantly reduced the in-terlayer coupling, and thus the assisting effect was suppressed. By optimizing the Pt thickness, the read-write test confirmed that the composite media with the proposed LSL presents superior recording performance over the conventional single layer media.
The third topic focuses on characterizing the magnetization reversal and the interfacial coupling of composite media. The depth-dependent magnetization reversal in composite media was directly probed by means of XMCD technique with a magnetization marker. When the LSL thickness is increased, the transition of magnetization reversal from rigid magnet to exchange spring is observed. By using polarized neutron reflectometry (PNR), we reveal that the hard and soft layers are largely decoupled with the increase of the LSL thickness, and much more tightly coupled when the LSL thickness drops. This finding is in agreement with the fact that the change in reversal behavior of composite media can be attributed to the interfacial coupling strength.

TABLE OF CONTENTS

ABSTRACT    I
ABSTRACT (IN CHINESE)    III
TABLE OF CONTENTS    V
LIST OF FIGURES    VIII
LIST OF TABLES    XIII
LIST OF ABBREVIATIONS    XIV
CHAPTER 1. INTRODUCTION    1
1 Motivation    2
2 Dissertation outline    4
CHAPTER 2. BACKGROUND    7
1 Perpendicular magnetic recording (PMR)    7
2 Recording disk    10
2.1. Substrate    11
2.2. Soft underlayer (SUL)    12
2.3. Intermediate layer (IL)    14
2.4. Recording layer (RL)    16
3 CoCr-based alloys    23
4 CoPtCr-oxide alloys    28
5 Composite recording media    35
5.1. Exchange coupled composite (ECC) media    36
5.2. Exchange spring media    42
CHAPTER 3. EXPERIMENTAL TECHNIQUES    51
1 Sample Fabrication    52
1.1. Ultra-High Vacuum DC/RF Sputtering System    52
2 Structure Characterization    53
2.1. X-Ray Diffractometer    53
2.2. Transmission Electron Microscope    54
2.3. Atomic Force Microscope    55
3 Magnetic Characterization    56
3.1. Vibrating Sample Magnetometer    56
3.2. Polar Magneto-Optic Kerr Effect Magnetometer (PMOKE)    58
3.3. First Order Reversal Curves    59
3.4. X-Ray Magnetic Circular Dichroism    61
3.5. Polarized Neutron Reflectometry    63
4 Compositional characterization    65
4.1. X-Ray Photoelectron Spectroscopy    65
4.2. X-Ray Absorption Spectroscopy    67
5 Read-Write Test    67
CHAPTER 4. EFFECTS OF OXIDE ADDITIVES AND SPUTTERING PROCESS ON INTER-GRAIN INTERACTION    69
1 Introduction    69
2 Experimental Procedures    70
3 Results and discussion    71
3.1. Role of oxide additive on the inter-grain interaction    71
3.2. Reactive sputtering process    83
4 Summary    86
CHAPTER 5. EXCHANGE COUPLED COMPOSITE MEDIA    89
1 Introduction    89
2 Experimental Procedures    91
3 Results and discussion    94
3.1. ECC media with laminated soft layer (LSL)    94
3.2. Recording performance of ECC media    104
4 Summary    109
CHAPTER 6. REVEALING MAGNETIZATION REVERSAL AND EXCHANGE COUPLING OF COMPOSITE MEDIA    111
1 Introduction    111
2 Experimental Procedure    113
3 Results and discussion    115
3.1. Effects of the thickness of the soft layer on ECC media    115
3.2. Magnetization reversal characterized by XMCD    122
3.3. Depth profile of interfacial coupling revealed by PNR    128
4 Summary    134
CHAPTER 7. CONCLUSIONS    135
REFERENCE    139
CURRICULUM VITAE    149
                                

1. S. Iwasaki and Y. Nakamura. An analysis for the magnetization mode for high density magnetic recording. IEEE Transactions on Magnetics, 13(5):1272–1277, 1977.–1277, SEP 1977.
2. T. P. Nolan, Y. Hirayama, and M. Futamoto. “Improvement of Co71Cr19Pt10/Ti90Cr10 perpendicular recording media by independent optimization of film nucleation and growth processes.” Journal of Applied Physics, 79(8, Part 2a):5359–5361, APR 1996.
3. K. Sato, H. Wakamatsu, and M. Shinohara. Noise characteristics of CoCrTa/NiFe perpendicular recording media. IEEE Transactions on Magnetics, 29(6):3730–3732, NOV 1993.
4. N. Honda, J. Ariake, K. Ouchi, and S. Iwasaki. Low noise Co-Cr-Nb perpendicular recording media with high squareness. IEEE Transactions on Magnetics, 34(4):1651–1653, JUL 1998.
5. H. Uwazumi, T. Shimatsu, Y. Sakai, A. Otsuki, I. Watanabe, H. Muraoka, and Y. Nakamura. Recording performance of CoCrPt-(Ta, B)/TiCr perpendicular recording media. IEEE Transactions on Magnetic, 37(4):1595–1598, JUL 2001.
6. M. Zheng, G. Choe, A. Chekanov, B. G. Demczyk, B. R. Acharya, and K. E. Johnson. SNR improvement of granular perpendicular recording media. IEEE Transactions on Magnetic, 39(4):1919–1924, JUL 2003
7. T. Chiba, J. Ariake, and N. Honda. Structure and magnetic properties of Co-Pt-Ta2O5 film for perpendicular magnetic recording media. Journal of Magnetism and Magnetic Materials, 287(SI):167–171, FEB 2005.
8. G. Choe, A. Roy, Z. Yang, B. R. Acharya, and E. N. Abarra. Magnetic and recording characteristics of reactively sputtered CoPtCr-(Si-O, Ti-O, and Cr-O) perpendicular media. IEEE Transactions on Magnetic, 42(10):2327–2329, OCT 2006.
9. H. J. Richter and A. Y. Dobin. Angle effects at high-density magnetic recording. Journal of Magnetism and Magnetic Materials, 287 (SI):41–50, FEB 2005
10. J. P Wang, W. K. Shen, J. M. Bai, R. H. Victora, J. H. Judy, and W. L. Song. Composite media (dynamic tilted media) for magnetic recording. Applied Physics Letters, 86(14):142504, APR 2005.
11. R. H. Victora and Xiao Shen. Composite media for perpendicular magnetic recording. IEEE Transactions on Magnetic, 41(2):537–542, FEB 2005.
12. D. Suess, T. Schrefl, S. Fahler, M. Kirschner, G. Hrkac, F. Dorfbauer, and J. Fidler. Exchange spring media for perpendicular recording. Applied Physics Letters, 87(1):012504, JUN 2005.
13. S. Iwasaki and K. Takemura. An analysis for the circular mode of magnetization in short wavelength recording. IEEE Transactions on Magnetics, 11(5):1173–1175, SEP 1975.
14. S. Iwasaki, Y. Nakamura, and K. Ouchi. Perpendicular magnetic recording with a composite anisotropy film. IEEE Transactions on Magnetics, 15(6):1456–1458, NOV 1979.
15. D. Litvinov, M. H. Kryder, and S. Khizroev. Recording physics of perpendicular media: hard layers. Journal of Magnetism and Magnetic Materials, 241(2-3):453–465, MAR 2002.
16. J. Desserre. Crucial points in perpendicular recording. IEEE Transactions on Magnetics, 20(5):663–668, JAN 1984.
17. T. Ando and T. Nishihara. Exchange-coupled CoZrNb/CoSm underlayer for perpendicular recording media. IEEE Transactions on Magnetics, 37(4):1228–1233, JUL 2001.
18. K. Tanahashi, A. Kikukawa, N. Shimizu, and Y. Hosoe. Reduction of spike noise in perpendicular recording media by using MnIr antiferromagnetic films. Journal of Applied Physics, 91(10):8049–8051, MAY 2002.
19. B. R. Acharya, J. N. Zhou, M. Zheng, G. Choe, E. N. Abarra, and K. E. Johnson. Anti-parallel coupled soft under layers for high-density perpendicular recording. IEEE Transactions on Magnetics, 40(4):2383–2385, JUL 2004.
20. D. Litvinov, M.H. Kryder, and S. Khizroev. Recording physics of perpendicular media: soft underlayers. Journal of Magnetism and Magnetic Materials, 232(1-2):84–90, JUN 2001.
21. Y. Honda, A. Kikukawa, Y. Hirayama, and M. Futamoto. Effect of soft magnetic underlayer on magnetization microstructure of perpendicular thin film media. IEEE Transactions on Magnetics, 36(5):2399–2401, SEP 2000.
22. N. Honda, J. Ariake, K. Ouchi, and S. Iwasaki. High coercivity in Co-Cr films for perpendicular recording prepared by low temperature sputter-deposition. IEEE Transactions on Magnetics, 30(6):4023–4025, NOV 1994
23. Y. Hirayama, M. Futamoto, K. Ito, Y. Honda, and Y. Maruyama. Development of high resolution and low noise single-layered perpendicular recording media for high density recording. IEEE Transactions on Magnetics, 33(1):996–1001, JAN 1997.
24. S. N. Piramanayagam. Perpendicular recording media for hard disk drives. Journal of Applied Physics, 102(1):011301, JUL 2007
25. J. Z. Shi, S. N. Piramanayagam, C. S. Mah, H. B. Zhao, J. M. Zhao, Y. S. Kay, and C. K. Pock. Influence of dual-Ru intermediate layers on magnetic properties and recording performance of CoCrPt–SiO2 perpendicular recording media. Applied Physics Letters, 87(22):222503, NOV 2005.
26. R. Mukai, T. Uzumaki, and A. Tanaka. Signal-to-media-noise ratio improvement of CoCrPt-SiO2 granular perpendicular media by stacked Ru underlayer. Journal of Applied Physics, 97(10, Part 3), MAY 2005.
27. Y. Honda, K. Tanahashi, Y. Hirayama, A. Kikukawa, and M. Futamoto. Observation of magnetic interaction between the soft magnetic and the recording layers in double-layer perpendicular media. IEEE Transactions on Magnetics, 37(4, Part 1):1315–1318, JUL 2001.
28. J. H. Judy. Advancements in PMR thin-film media. Journal of Magnetism and Magnetic Materials, 287(2005):16–26, OCT 2004.
29. T. Klemmer, Y. Peng, X. Wu, and G. Ju. Materials Processing for High Anisotropy L10 Granular Media. IEEE Transactions on Magnetics, 45(2):845–849, FEB 2009.
30. D. Weller, A. Moser, L. Folks, M. E. Best, Wen Lee, M. F. Toney, M. Schwickert, J.-U. Thiele, and M. F. Doerner. High Ku materials approach to 100 Gbits/in2. IEEE Transactions on Magnetics, 36(1):10–15, JAN 2000.
31. R.E. Rottmayer, S. Batra, D. Buechel, W.A. Challener, J. Hohlfeld, Y. Kubota, L. Li, B. Lu, C. Mihalcea, K. Mountfield, K. Pelhos, C. Peng, T. Rausch, M.A. Seigler, D. Weller, and X. Yang. Heat-assisted magnetic recording. IEEE Transactions on Magnetics, 42(10):2417–2421, OCT 2006.
32. K. Ouchi and N. Honda. Overview of latest work on perpendicular recording media. IEEE Transactions on Magnetics, 36(1):16–22, JAN 2000.
33. Kitakami and Y. Shimada. On magnetization reversal of Co-Cr films with perpendicular anisotropy. Japanese Journal of Applied Physics, 40(6A):4019–4022, JUN 2001.
34. H. J. Richter. The transition from longitudinal to perpendicular recording. Journal of Physics D: Applied Physics, 40(9):R149, APR 2007.
35. S. Takenoiri, Y. Sakai, K. Enomoto, S. Watanabe, and H. Uwazumi. Magnetic properties, magnetic cluster size, and read-write performance of CoPtCr-SiO2 perpendicular recording media. IEEE Transactions on Magnetics, 39(5):2279–2281, SEP 2003.
36. X. W. Wu, Yingguo Peng, and Binquan Wang. Magnetic cluster size and cluster size distribution study on perpendicular media. Applied Physics Letters, 93(15):152514, OCT 2008.
37. Y. Hirayama, M. Futamoto, K. Kimoto, and K. Usami. Compositional microstructures of CoCr-alloy perpendicular magnetic recording media. IEEE Transactions on Magnetics, 32(5):3807–3809, SEP 1996.
38. J. Ariake, N. Honda, K. Ouchi, and S.-I. Iwasaki. Preparation of double-layered perpendicular media for fine magnetic structure. IEEE Transactions on Magnetics, 36(5):2411–2413, SEP 2000.
39. G. A. Bertero, D. Wachenschwanz, S. Malhotra, S. Velu, B. Bian, D. Stafford, Yan Wu, T. Yamashita, and S. X. Wang. Optimization of granular doublelayer perpendicular media. IEEE Transactions on Magnetics, 38(4):1627–1631, JUL 2002.
40. T. Shimatsu, H. Uwazumi, Y. Sakai, A. Otsuki, I. Watanabe, H. Muraoka, and Y. Nakamura. Thermal agitation of magnetization in CoCrPt perpendicular recording media. IEEE Transactions on Magnetics, 37(4):1567–1569, JUL 2001.
41. J. Ariake, N. Honda, and K. Ouchi, Low noise recording medium design with Co-Cr-Nb film, Journal of the Magnetic Society of Japan, 21(S2), 509–512, JUL 1997.
42. N. Honda, S. Yanase, K. Ouchi, and S. Iwasaki. Study on recording beyond 10 Gbit/in.2 with Co-Cr based perpendicular recording media. Journal of Applied Physics, 85(8):6130–6132, APR 1999.
43. Y. Hirayama, K. Ito, Y. Honda, and M. Futamoto. Magnetization decay in CoCr-alloy perpendicular magnetic recording media. Journal of the Magnetic Society of Japan, 21(S2):297–300, SEP 1997.
44. H. Futamoto, Y. Hirayama, N. Inaba, Y. Honda, K. Ito, A. Kikugawa, and T. Takeuchi. Thermal stability of magnetic recording in perpendicular thin film media. IEEE Transactions on Magnetics, 35(5, Part 1):2802–2807, SEP 1999.
45. J. Ariake, N. Honda, and K. Ouchi. Pt/C intermediate layer for Co-Cr perpendicular magnetic recording media with extremely high resolution. IEEE Transactions on Magnetics, 39(5):2294–2296, SEP 2003
46. B. Lu, D. Weller, A. Sunder, G. Ju, X. Wu, R. Brockie, T. Nolan, C. Brucker, and R. Ranjan. High anisotropy CoCrPt(B) media for perpendicular magnetic recording. Journal of Applied Physics, 93(10):6751–6753, MAY 2003.
47. Y. Sonobe, D. Weller, Y. Ikeda, M. Schabes, K. Takano, G. Zeltzer, B. K. Yen, M. E. Best, S. J. Greaves, H. Muraoka, and Y. Nakamura. Thermal stability and SNR of coupled granular/continuous media. IEEE Transactions on Magnetics, 37(4):1667–1670, JUL 2001.
48. Y. Sonobe, H. Muraoka, K. Miura, Y. Nakamura, K. Takano, H. Do, A. Moser, B. K. Yen, Y. Ikeda, and N. Supper. Coupled granular/continuous perpendicular recording media with soft magnetic underlayer. Journal of Applied Physics, 91(10):8055–8057, MAY 2002.
49. S. Oikawa, A. Takeo, T. Hikosaka, and Y. Tanaka. High performance CoPtCrO single layered perpendicular media with no recording demagnetization. IEEE Transactions on Magnetics, 36(5):2393–2395, SEP 2000.
50. T. Oikawa, M. Nakamura, H. Uwazumi, T. Shimatsu, H. Muraoka, and Y. Nakamura. Microstructure and magnetic properties of CoPtCr-SiO2 perpendicular recording media. IEEE Transactions on Magnetics, 38(5, Part 1):1976–1978, SEP 2002.
51. M. Zheng, B. R. Acharya, G. Choe, J. N. Zhou, Z. D. Yang, E. N. Abarra, and K. E. Johnson. Role of oxygen incorporation in Co-Cr-Pt-Si-O perpendicular magnetic recording media. IEEE Transactions on Magnetics 40(4, Part 2):2498–2500, JUL 2004.
52. Y. Inaba, T. Shimatsu, S. Oikawa, H. Sato, H. Aoi, H. Muraoka, and Y. Nakamura. Optimization of the SiO2 content in CoPtCr-SiO2 perpendicular recording media for high-density recording. IEEE Transactions on Magnetics,40 (4, Part 2):2486–2488, JUL 2004.
53. S. N. Piramanayagam, J. Z. Shi, H. B. Zhao, C. S. Mah, and J. Zhang. Stacked CoCrPt:SiO2 layers for perpendicular recording media. IEEE Transactions on Magnetics, 41(10):3190–3192, OCT 2005.
54. B. R. Acharya, M. Zheng, G. Choe, M. Yu, P. Gill, and E. N. Abarra. Anisotropy enhanced dual magnetic layer media design for high-density perpendicular recording. IEEE Transactions on Magnetics, 41(10):3145–3147, OCT 2005.
55. G. Choe, M. Zheng, B. R. Acharya, E. N. Abarra, and J. N. Zhou. Perpendicular recording CoPtCrO composite media with performance enhancement capping layer. IEEE Transactions on Magnetics, 41 (10):3172–3174, OCT 2005.
56. Tamai, R. Araki, and K. Tanahashi. Magnetic and recording characteristics of CoCrPt-oxide media with a mixture of SiO2 and TiO2. IEEE Transactions on Magnetics, 44(11):3492–3495, NOV 2008.
57. V. Sokalski, D. E. Laughlin, and J. G. Zhu. Experimental modeling of intergranular exchange coupling for perpendicular thin film media. Applied Physics Letters, 95(10):102507, SEP 2009.
58. J. G. Zhu, X. Zhu, and Y. Tang. Microwave assisted magnetic recording. IEEE Transactions on Magnetics, 44(1):125–131, JAN 2008.
59. J. P. Wang, W. Shen, and J. Bai. Exchange coupled composite media for perpendicular magnetic recording. IEEE Transactions on Magnetics, 41 (10):3181–3186, OCT 2005
60. K. Z. Gao and H. N. Bertram. Magnetic recording configuration for densities beyond 1 Tb/in2 and data rates beyond 1 Gb/s. IEEE Transactions on Magnetics, 38(6):3675–3683, NOV 2002.
61. J. P. Wang, W. Shen, and S. Y. Hong. Fabrication and characterization of exchange coupled composite media. IEEE Transactions on Magnetics, 43(2):682–686, FEB 2007.
62. E. F. Kneller and R. Hawig. The exchange spring magnet a new material principle for permanent magnets. IEEE Transactions on Magnetics, 27(4):3588–3600, JUL 1991.
63. Yu. Dobin and H. J. Richter. Domain wall assisted magnetic recording. Applied Physics Letters, 89(6):062512, AUG 2006.
64. G Asti, M Ghidini, R Pellicelli, C Pernechele, M Solzi, F Albertini, F Casoli, S Fabbrici, and L Pareti. Magnetic phase diagram and demagnetization processes in perpendicular exchange-spring multilayers. Physical Review B, 73(9):094406, MAR 2006.
65. H. Kronmuller and D. Goll. Micromagnetic theory of the pinning of domain walls at phase boundaries. Physica B-Condensed Matter, 319(1-4):122–126, JUL 2002
66. D. Suess, J. Lee, J. Fidler, and T. Schrefl. Exchange-coupled perpendicular media. Journal of Magnetism And Magnetic Materials, 321(6):545–554, MAR 2009.
67. D. Suess, T. Schrefl, R. Dittrich, M. Kirschner, F. Dorfbauer, G. Hrkac, and J. Fidler. Exchange spring recording media for areal densities up to 10 Tbit/in2. Journal of Magnetism And Magnetic Materials, 290(Part 1, SI):551–554, APR 2005
68. D. Suess. Multilayer exchange spring media for magnetic recording. Applied Physics Letters, 89(11):113105, SEP 2006.
69. D. Goll and S. Macke. Thermal stability of ledge-type L10-FePt/Fe exchange-spring nanocomposites for ultrahigh recording densities. Applied Physics Letters, 93(15):152512, OCT 2008.
70. E. Girt, A. Yu. Dobin, B. Valcu, H. J. Richter, X. Wu, and T. P. Nolan. Experimental evidence of domain wall assisted switching in composite media. IEEE Transactions on Magnetics, 43(6):2166–2168, JUN 2007.
71. J. E. Davies, O. Hellwig, E. E. Fullerton, J. S. Jiang, S. D. Bader, G. T. Zimanyi, and K. Liu. Anisotropy dependence of irreversible switching in Fe/SmCo and FeNi/FePt exchange spring magnet films. Applied Physics Letters, 86(26), JUN 2005.
72. S. M. Watson, T. Hauet, J. A. Borchers, S. Mangin, and Eric E. Fullerton. Interfacial magnetic domain wall formation in perpendicular-anisotropy, exchange-spring films. Applied Physics Letters, 92(20):202507, MAY 2008.
73. Y. Choi, J. S. Jiang, J. E. Pearson, S. D. Bader, J. J. Kavich, J. W. Freeland, and J. P. Liu. Controlled interface profile in Sm-Co/Fe exchange-spring magnets. Applied Physics Letters, 91(7):072509, AUG 2007.
74. S. Foner. Versatile And Sensitive Vibrating-Sample Magnetometer. Review of Scientific Instruments, 30(7):548–557, MAY 1959.
75. C. R. Pike, A. P. Roberts, and K. L. Verosub. Characterizing interactions in fine magnetic particle systems using first order reversal curves. Journal of Applied Physics, 85(9):6660–6667, MAY 1999.
76. C. R. Pike. First-order reversal-curve diagrams and reversible magnetization. Physical Review B, 68(10):104424, SEP 2003.
77. G. Schutz, W. Wagner, W. Wilhelm, P. Kienle, R. Zeller, R. Frahm, And G. Materlik. Absorption of circularly polarized x-rays in iron. Physical Review Letters, 58(7):737–740, FEB 1987.
78. J. Stohr, Y. Wu, B. D. Hermsmeier, M. G. Samant, G. R. Harp, S. Koranda, D. Dunham, and B. P. Tonner. Element-specific magnetic microscopy with circularly polarized X-rays. Science, 259(5095):658–661, Jan 1993.
79. J. Stohr. Exploring the microscopic origin of magnetic anisotropies with X-ray magnetic circular dichroism (XMCD) spectroscopy. Journal of Magnetism and Magnetic Materials, 200(1-3):470–497, OCT 1999.
80. C. T. Chen, Y. U. Idzerda, H. J. Lin, N. V. Smith, G. Meigs, E. Chaban, G. H. Ho, E. Pellegrin, and F. Sette. Experimental confirmation of the X-ray magnetic circular-dichroism sum-rules for iron and cobalt. Physical Review Letters, 75(1):152–155, JUL 1995.
81. C. F. Majkrzak. Polarized neutron reflectometry. Physica B, 173(1-2):75–88, AUG 1991.
82. B. J. Kirby, J. E. Davies, Kai Liu, S. M. Watson, G. T. Zimanyi, R. D. Shull, P. A. Kienzle, and J. A. Borchers. Vertically graded anisotropy in Co/Pd multilayers. Physical Review B, 81(10):100405(R), MAR 2010.
83. C. Nordling, E. Sokolowski, and K. Siegbahn. Precision method for obtaining absolute values of atomic binding energies. Physical Review, 105(5):1676–1677, JAN 1957.
84. G. Vanderlaan and I. W. Kirkman. The 2p absorption-spectra of 3d transition-metal compounds in tetrahedral and octahedral symmetry. Journal of Physics-Condensed Matter, 4(16):4189–4204, APR 1992.
85. H. C. Hou, J. W. Liao, L. W. Wang, R. Z. Chen, C. H. Chiu, H. J. Lin, F. H. Chang, and C. H. Lai. Effects of oxide additives on inter-grain interaction of CoPtCr-oxide. Journal of Applied Physics, 111(7):07B725, MAR 2012.
86. J. E. Davies, O. Hellwig, E. E. Fullerton, G. Denbeaux, J. B. Kortright, and K. Liu. Magnetization reversal of Co/Pt multilayers: Microscopic origin of high-field magnetic irreversibility. Physical Review B, 70(22):224434, DEC 2004.
87. C. R. Pike, C. A. Ross, R. T. Scalettar, and G. Zimanyi. First-order reversal curve diagram analysis of a perpendicular nickel nanopillar array. Physical Review B, 71(13), APR 2005.
88. T. Iwasaki, S. Oikawa, F. Nakamura, T. Maeda, H. Sakai, A. Sakawaki, and K. Simizu. Perpendicular magnetic recording medium and magnetic recording/reproducing apparatus, US patent, No.US7601445 B2, OCT 2009.
89. P. J. Flanders and M. P. Sharrock, An analysis of time-dependent magnetization and coercivity and of their relationship to print-through in recording tapes. Journal of Applied Physics, 62(7):2918–2928, OCT 1987.
90. M. P. Sharrock, Time-dependence of switching fields in magnetic recording media (invited). Journal of Applied Physics, 76(10, Part 2):6413–6418, NOV 1994.
91. M. Igarashi and Y. Sugita, Validity of values of thermal stability and switching field in recording medium obtained by using Sharrock’s formula. IEEE Transactions on Magnetics, 42(10):2399–2401, OCT 2006.
92. S. Hong, X. Che, Y. Tang, and J.-G. Zhu. Reduction of adjacent track encroachment in exchange coupled composite media through soft magnetic layer with high Ku. Journal of Applied Physics, 103(7):07F530, APR 2008.
93. Y. Tang, J.-G. Zhu, S. Hong, and X. Che. Optimization of perpendicular recording on exchange coupled composite media. Journal of Applied Physics, 103(7):07F527, APR 2008.
94. H. C. Hou, M. S. Lin, J. W. Liao, T. L. Wu, C. H. Lai, R. Z. Chen, J. L. Lee, H. J. Lin, F. H. Chang, and J. S. Yang. Effects of laminated soft layer on magnetization reversal of exchange coupled composite media. Journal of Applied Physics, 105(7):07B729, MAR 2009.
95. H. C. Hou, J. W. Liao, M. S. Lin, H. J. Lin, F. H. Chang, R. Z. Chen, C. H. Chiu, and C. H. Lai. Optimization of exchange coupled composite media by tuning the anisotropy in a laminated soft layer. Journal of Applied Physics, 109(7):07C104, MAR 2011.
96. H. S. Jung, S. S. Malhotra, B. R. Acharya, G. Bertero, and D. Suess. Effect of magnetic softness in a soft layer on media properties of hard/soft stacked composite perpendicular media. Journal of Applied Physics, 105(7):07B740, APR 2009.
97. E. F. Kneller and R. Hawig. The exchange spring magnet a new material principle for permanent magnets. IEEE Transactions on Magnetics, 27(4):3588–3600, JUL 1991.
98. C. F. Majkrzak et al., in Neutron Scattering From Magnetic Materials, edited by T. Chatterji (Elsevier Science, New York, 2005).
99. http://reflectometry.org/danse/software.html
100. H. C. Hou, D. Suess, J. W. Liao, M. S. Lin, H. J. Lin, F. H. Chang, and C. H. Lai. Direct probing magnetization reversal of exchange-coupled-composite media by x-ray magnetic circular dichroism. Applied Physics Letters, 98(26):262507, JUL 2011.
101. T. Hauet, S. Florez, D. Margulies, Y. Ikeda, B. Lengsﬁeld, N. Supper, K. Takano,O. Hellwig, and B. D. Terris. Revealing the reversible rotation of magnetization in ex-change-coupled composite media switching. Applied Physics Letters, 95(22):222507, NOV 2009.
102. D. Suess. Micromagnetics of exchange spring media: Optimization and limits. Journal of Magnetism and Magnetic Materials, 308(2):183–197, JAN 2007.
103. K. V. O’Donovan, J. A. Borchers, C. F. Majkrzak, O. Hellwig, and E. E. Fullerton. Pinpointing chiral structures with front-back polarized neutron reflectometry. Physical Review Letters, 88(6):067201, FEB 2002.
104. Y. Liu, S. G. E. Te Velthuis, J. S. Jiang, Y. Choi, S. D. Bader, A. A. Parizzi, H. Ambaye, and V. Lauter. Magnetic structure in Fe/Sm-Co exchange spring bilayers with intermixed interfaces. Physical Review B, 83(17):174418, MAY 2011.
105. B. J. Kirby, S. M. Watson, J. E. Davies, G. T. Zimanyi, Kai Liu, R. D. Shull, and J. A. Borchers. Direct observation of magnetic gradient in Co/Pd pressure-graded media. Journal of Applied Physics, 105(7):07C929, APR 2009.

全文公開日期本全文未授權公開 (校內網路)
全文公開日期本全文未授權公開 (校外網路)

簡易檢索 / 詳目顯示

相關論文