超低飞高硬盘头盘系统稳定性研究
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摘要
自1956年IBM发明第一块硬盘以来,硬盘技术取得了突飞猛进的发展,硬盘的应用也越来越广泛。自二十世纪九十年代,硬盘面密度保持60%的年增长率增长。特别是1998年后,随着GMR (Giant Magneto Resistance)磁头的引入,面密度年增长率更是达到了100%。随着存储密度的不断提高,硬盘磁头与盘片之间的距离(即磁头飞行高度)必须更低。当磁头飞行高度降低到10 nm以下时,传统的空气薄膜润滑模型遇到挑战,磁头与盘片界面短程作用力对磁头运动产生重要影响,特别是分子间作用力。
从两分子的分子间作用力模型出发,结合磁头盘片界面多层结构,推导磁头盘片界面分子间作用力模型。鉴于分子间作用力会降低磁头盘片系统空气轴承承载力,同时引起磁头运动的不稳定性,继而在所得磁头盘片界面分子间作用力模型基础上研究了润滑剂层厚度、磁头飞行倾角和滚翻角以及空气轴承表面(air bearing surface,ABS)形状等相关因素对分子间作用力的影响。
通过系统仿真,结果表明:添加润滑层可以明显降低磁头盘片界面分子间作用力;分子间作用力随磁头飞行倾角和滚翻角的增加而减小,在条件允许的情况下应尽量增加磁头飞行倾角和滚翻角;ABS形状对磁头盘片界面分子间作用力有显著影响,在不影响滑块空气动力学特性的情况下应尽量减小其尾部垫片的面积。仿真结果为指导实际高密度硬盘头盘系统设计提供了理论依据。
Since IBM invented the first hard disk drive(HDD) in 1956, the development of hard disk technology is amazing, and the applications of hard disks is more and more extensive. The areal density increased at a rate of 60% per year after 1990. Especially, the areal density increased at a rate of 100% per year since the GMR head was introduced in 1998. With the areal density increased continually, the distance between the head and disk had to be reduced. When the flying height is lower than 10 nm, traditional air bearing lubricant model faces to a challenge, and the short-range forces between the head and disk surface have great effect to the motion of the head, especially the intermolecular force.
In this paper the intermolecular force model between the head and disk is derived from the intermolecular force model between two molecules Lennard-Jones potential based on the multilayer structure of the head disk system. As intermolecular force will reduce the adhesion force of the air bearing of the head disk system and cause the instability of the head, the influences of the intermolecular force on head-disk interface are analyzed in detail, such as the thickness of the lubricant film, the pitch angle, the roll angle and the air bearing surface.
Numerical simulation results show that: a lubricant film reduces the intermolecular force greatly, however a further increase of the lubricant film thickness only gives a minor reduction of the intermolecular force; Increase of pitch angle and roll angle will reduce the intermolecular force; ABS affects the intermolecular force greatly and the intermolecular force can be reduced by reducing the trailing pad of ABS. This provides a theory basis for the design of air bearing slider with high recording density.
从两分子的分子间作用力模型出发,结合磁头盘片界面多层结构,推导磁头盘片界面分子间作用力模型。鉴于分子间作用力会降低磁头盘片系统空气轴承承载力,同时引起磁头运动的不稳定性,继而在所得磁头盘片界面分子间作用力模型基础上研究了润滑剂层厚度、磁头飞行倾角和滚翻角以及空气轴承表面(air bearing surface,ABS)形状等相关因素对分子间作用力的影响。
通过系统仿真,结果表明:添加润滑层可以明显降低磁头盘片界面分子间作用力;分子间作用力随磁头飞行倾角和滚翻角的增加而减小,在条件允许的情况下应尽量增加磁头飞行倾角和滚翻角;ABS形状对磁头盘片界面分子间作用力有显著影响,在不影响滑块空气动力学特性的情况下应尽量减小其尾部垫片的面积。仿真结果为指导实际高密度硬盘头盘系统设计提供了理论依据。
Since IBM invented the first hard disk drive(HDD) in 1956, the development of hard disk technology is amazing, and the applications of hard disks is more and more extensive. The areal density increased at a rate of 60% per year after 1990. Especially, the areal density increased at a rate of 100% per year since the GMR head was introduced in 1998. With the areal density increased continually, the distance between the head and disk had to be reduced. When the flying height is lower than 10 nm, traditional air bearing lubricant model faces to a challenge, and the short-range forces between the head and disk surface have great effect to the motion of the head, especially the intermolecular force.
In this paper the intermolecular force model between the head and disk is derived from the intermolecular force model between two molecules Lennard-Jones potential based on the multilayer structure of the head disk system. As intermolecular force will reduce the adhesion force of the air bearing of the head disk system and cause the instability of the head, the influences of the intermolecular force on head-disk interface are analyzed in detail, such as the thickness of the lubricant film, the pitch angle, the roll angle and the air bearing surface.
Numerical simulation results show that: a lubricant film reduces the intermolecular force greatly, however a further increase of the lubricant film thickness only gives a minor reduction of the intermolecular force; Increase of pitch angle and roll angle will reduce the intermolecular force; ABS affects the intermolecular force greatly and the intermolecular force can be reduced by reducing the trailing pad of ABS. This provides a theory basis for the design of air bearing slider with high recording density.
引文
[1] Judy J H. Past, present, and future of perpendicular magnetic recording. Journal of Magnetism and Magnetic Materials. 2001, 235( 1): 235~240
[2]蒋致诚.硬盘驱动器巨磁电阻(GMR)磁头:从微米到纳米.物理学与高新技术, 2004, 33(7): 529~533
[3] Wood R. The feasibility of magnetic recording at 1 terabit per square inch, IEEE Transactions on Magnetics, 2000, 36(1): 36~42
[4] Reynolds O. On the theory of lubrication and its application to Mr. Beauchamp Tower’s experiments including an experimental determination of the viscosity of olive oil. Philosophical Transaction of the Royal Society of London, 1886, 177(1):157~234
[5] Burgdorfer A. The influence of the molecular mean free path on the performance of hydrodynamic gas lubricated bearing. ASME, J Basic, 1959, 81(3): 94~100
[6] Hsia Y T, Domoto G A. An experimental investigation of molecular rarefaction effects in gas lubricated bearing at ultra-low clearances. ASME Transaction Journal of Tribology, 1983, 105(1):120~130
[7] Mitsuya Y. Modified reynolds equation for ultra-thin film gas lubrication using 1.5-order slip-flow model and considering surface accommodatio coefficient. Journal of Tribology, 1993, 115(2): 289~293
[8] Gans R F. Lubrication theory at arbitrary knudsen number. ASME Transaction Journal of Tribology, 1985, 107(3): 431~433
[9] Fukui S, Kaneko R. Analysis of ultra-thin gas film lubrication based on linearized boltzmann equation: first report derivation of a generalized lubrication equation including thermal creep flow. Journal of Tribology, 1988, 110(2): 253~261
[10] Kogure K, Fukui S, Mitsuya Y, et al. Design of negative pressure slider for magnetic recording disk. ASME Journal of Lubricat Technol, 1983, 105(3): 496~502
[11] Masahiro K, Ohtsubo Y, Kawashima N. Finite element solution for the rarefied gaslubrication problem. ASME Transaction Journal of Tribology, 1988, 110(2): 335~341
[12] Wu L, Bogy D B. Unstructured triangular mesh generation techniques and a finite volume numerical scheme for slider air bearing simulation with complex shaped rails. IEEE Transactions on Magnetics, 1999, 35(5): 2421~2423
[13] Li Jianhua, Liu Bo, Hua Wei, et al. Effects of intermolecualr forces on deep sub-10 nm space sliders, IEEE Transactions on Magnetics, 2002, 38(5): 2141~2143
[14] Kubotera H, Bogy D B. Numerical simulation of molecularly thin lubricant film flow due to the air bearing slider in hard disk drives, Microsyst Technol, 2007, 13(1): 859~865
[15] Li H, Liu B, Hua W, Chong T C. Intermolecular force, surface roughness, and stability of head-disk interface. Journal of applied physics, 2005, 97(3): 105~108
[16] Gupta V, Bogy D B. Dynamics of sub-5-nm air-bearing sliders in the presence of electrostatic and intermolecular forces at the head-disk interface. IEEE Transactions on Magnetics, 2005, 41(2): 610~615
[17] Liu Bo, Yu Shengkai, Zhang Mingsheng, et al. Air bearing design towards highly stable head-disk interface at ultra-low flying height. IEEE Transactions on Magnetics, 2007, 43(2):715~720
[18] Li Jianhua, Liu Bo, Hua Wei, et al. Effects of intermolecular forces on deep sub-10 nm spaced slider. IEEE Transactions on Magnetics, 2002, 38(5): 2141~2143
[19] Thornton B H, Bogy D B. A parametric study of head-disk interface instability due to intermolecular forces. IEEE Transactions on Magnetics, 2004, 40(1): 337~344
[20] Li Hui, Liu Bo, Hua Wei, et al. Intermolecular force, surface roughness, and stability of head-disk interface. Journal of Applied Physics, 2005, 97(10): 305~310
[21]宁章.计算机外部设备及网络设备.北京:北京航空航天大学出版社, 2001, 10~56
[22]青玉案.硬盘内部世界漫游记.电脑爱好者, 2005, 66(16): 85~86
[23] Liu Bo, Liu Jin, Chong Tow-Chong. Slider design for sub-3-nm flying height head-disk systems. Journal of Magnetism and Magnetic Materials, 2005, 287(2):339~345
[24] Mohamed G. The fluid mechanics of microdevices-the freeman scholar lecture, Journal of Fluids Engineering. 1999 121(4): 5~32
[25]方文定.高密度硬盘磁头形状优化设计[硕士学位论文].南京:东南大学图书馆, 2006, 3~5
[26] Richter H J. Longitudinal recording at 10 to 20 Gbit/inch2 and beyond. IEEE Transactions on Magnetics, 1999, 35(5): 2790~2795
[27] Tanaka Y. Perpendicular recording technology: from research to commercialization. IEEE Transactions on Magnetics, 2008, 96(11): 1754~1760
[28] Liu F, Stoev K, Peng L, et al. Perpendicular recording heads for extremely high-density recording. IEEE Transactions on Magnetics, 2003, 39(4): 1942~1948
[29] Xiao Peiyun. Simulation study of magnetic media nanostructure and its recording performance, National university of singapore, 2005, 1~20
[30]李鸿秋,史宝军.磁头气膜浮动块浮动特性的影响因素.电脑知识与技术, 2006, 2006(8): 97~99
[31] Alexander F J, Garcia A L, Alder B J. Direct simulation Mont Carlo for thin-film bearings, Phys.Fluids, 1994, 6(12): 3854~3860
[32] Li Xuhong, Du Hejun, Liu Bo, et al. Numerical simulation of slider air bearings based on a mesh-free method for HDD applications. Microsystem Technologies, 2005, 11(2):797-804
[33] George Em Karniadakis, Ali Beskok.微流动基础与模拟.北京:化学工业出版社, 2006, 12~61
[34]秦允豪.热学.北京:高等教育出版社. 2004, 52~90
[35] Thornton B H, Bogy D B. Head-disk interface dynamic instability due to intermolecular forces. IEEE Transactions on Magnetics, 2003, 39(5): 2420~2422
[36] Gupta V. Air bearing slider dynamics and stability in hard disk drives. University of California, Berkeley, 2007, 50~52
[37]蒋硕健,丁有骏,李明谦.有机化学.北京:北京大学出版社, 1999, 15~81
[38] Israelachvili J N. Intermolecular and surface forces. Academic Press, San Diego,1992, 9~39
[39] Ma X, Chen J, Richter JH, et al. Contribution of lubricant thickness to head-media spacing. IEEE Transactions on Magnetics, 2001, 37(4):1824~1826
[40]唐微微,孟永刚.范德华力对计算机磁头磁盘超薄气膜承载性能的影响.摩擦学学报, 2007, 27(1): 6~10
[41]张会臣,雒建斌.硬盘润滑剂性能及其对磁记录系统动力学特性的影响研究进展.摩擦学学报, 2004, 24(5): 476~482
[42] Zhang B, Nakajima A. Possibility of surface force effect in slider air bearing of 100Gbit/in2 hard disks. Tribology Intermational, 2003, 36(4): 291~296
[43] Choi D H, Kang T S. An optimization method for design of subambient pressure shaped rail sliders, Journal of Tribology, 1999, 3(1): 575~579
[44] Ross C. Patterned magnetic recording media. Annual Review of Materials Research, 2001, 31(1): 203~235
[2]蒋致诚.硬盘驱动器巨磁电阻(GMR)磁头:从微米到纳米.物理学与高新技术, 2004, 33(7): 529~533
[3] Wood R. The feasibility of magnetic recording at 1 terabit per square inch, IEEE Transactions on Magnetics, 2000, 36(1): 36~42
[4] Reynolds O. On the theory of lubrication and its application to Mr. Beauchamp Tower’s experiments including an experimental determination of the viscosity of olive oil. Philosophical Transaction of the Royal Society of London, 1886, 177(1):157~234
[5] Burgdorfer A. The influence of the molecular mean free path on the performance of hydrodynamic gas lubricated bearing. ASME, J Basic, 1959, 81(3): 94~100
[6] Hsia Y T, Domoto G A. An experimental investigation of molecular rarefaction effects in gas lubricated bearing at ultra-low clearances. ASME Transaction Journal of Tribology, 1983, 105(1):120~130
[7] Mitsuya Y. Modified reynolds equation for ultra-thin film gas lubrication using 1.5-order slip-flow model and considering surface accommodatio coefficient. Journal of Tribology, 1993, 115(2): 289~293
[8] Gans R F. Lubrication theory at arbitrary knudsen number. ASME Transaction Journal of Tribology, 1985, 107(3): 431~433
[9] Fukui S, Kaneko R. Analysis of ultra-thin gas film lubrication based on linearized boltzmann equation: first report derivation of a generalized lubrication equation including thermal creep flow. Journal of Tribology, 1988, 110(2): 253~261
[10] Kogure K, Fukui S, Mitsuya Y, et al. Design of negative pressure slider for magnetic recording disk. ASME Journal of Lubricat Technol, 1983, 105(3): 496~502
[11] Masahiro K, Ohtsubo Y, Kawashima N. Finite element solution for the rarefied gaslubrication problem. ASME Transaction Journal of Tribology, 1988, 110(2): 335~341
[12] Wu L, Bogy D B. Unstructured triangular mesh generation techniques and a finite volume numerical scheme for slider air bearing simulation with complex shaped rails. IEEE Transactions on Magnetics, 1999, 35(5): 2421~2423
[13] Li Jianhua, Liu Bo, Hua Wei, et al. Effects of intermolecualr forces on deep sub-10 nm space sliders, IEEE Transactions on Magnetics, 2002, 38(5): 2141~2143
[14] Kubotera H, Bogy D B. Numerical simulation of molecularly thin lubricant film flow due to the air bearing slider in hard disk drives, Microsyst Technol, 2007, 13(1): 859~865
[15] Li H, Liu B, Hua W, Chong T C. Intermolecular force, surface roughness, and stability of head-disk interface. Journal of applied physics, 2005, 97(3): 105~108
[16] Gupta V, Bogy D B. Dynamics of sub-5-nm air-bearing sliders in the presence of electrostatic and intermolecular forces at the head-disk interface. IEEE Transactions on Magnetics, 2005, 41(2): 610~615
[17] Liu Bo, Yu Shengkai, Zhang Mingsheng, et al. Air bearing design towards highly stable head-disk interface at ultra-low flying height. IEEE Transactions on Magnetics, 2007, 43(2):715~720
[18] Li Jianhua, Liu Bo, Hua Wei, et al. Effects of intermolecular forces on deep sub-10 nm spaced slider. IEEE Transactions on Magnetics, 2002, 38(5): 2141~2143
[19] Thornton B H, Bogy D B. A parametric study of head-disk interface instability due to intermolecular forces. IEEE Transactions on Magnetics, 2004, 40(1): 337~344
[20] Li Hui, Liu Bo, Hua Wei, et al. Intermolecular force, surface roughness, and stability of head-disk interface. Journal of Applied Physics, 2005, 97(10): 305~310
[21]宁章.计算机外部设备及网络设备.北京:北京航空航天大学出版社, 2001, 10~56
[22]青玉案.硬盘内部世界漫游记.电脑爱好者, 2005, 66(16): 85~86
[23] Liu Bo, Liu Jin, Chong Tow-Chong. Slider design for sub-3-nm flying height head-disk systems. Journal of Magnetism and Magnetic Materials, 2005, 287(2):339~345
[24] Mohamed G. The fluid mechanics of microdevices-the freeman scholar lecture, Journal of Fluids Engineering. 1999 121(4): 5~32
[25]方文定.高密度硬盘磁头形状优化设计[硕士学位论文].南京:东南大学图书馆, 2006, 3~5
[26] Richter H J. Longitudinal recording at 10 to 20 Gbit/inch2 and beyond. IEEE Transactions on Magnetics, 1999, 35(5): 2790~2795
[27] Tanaka Y. Perpendicular recording technology: from research to commercialization. IEEE Transactions on Magnetics, 2008, 96(11): 1754~1760
[28] Liu F, Stoev K, Peng L, et al. Perpendicular recording heads for extremely high-density recording. IEEE Transactions on Magnetics, 2003, 39(4): 1942~1948
[29] Xiao Peiyun. Simulation study of magnetic media nanostructure and its recording performance, National university of singapore, 2005, 1~20
[30]李鸿秋,史宝军.磁头气膜浮动块浮动特性的影响因素.电脑知识与技术, 2006, 2006(8): 97~99
[31] Alexander F J, Garcia A L, Alder B J. Direct simulation Mont Carlo for thin-film bearings, Phys.Fluids, 1994, 6(12): 3854~3860
[32] Li Xuhong, Du Hejun, Liu Bo, et al. Numerical simulation of slider air bearings based on a mesh-free method for HDD applications. Microsystem Technologies, 2005, 11(2):797-804
[33] George Em Karniadakis, Ali Beskok.微流动基础与模拟.北京:化学工业出版社, 2006, 12~61
[34]秦允豪.热学.北京:高等教育出版社. 2004, 52~90
[35] Thornton B H, Bogy D B. Head-disk interface dynamic instability due to intermolecular forces. IEEE Transactions on Magnetics, 2003, 39(5): 2420~2422
[36] Gupta V. Air bearing slider dynamics and stability in hard disk drives. University of California, Berkeley, 2007, 50~52
[37]蒋硕健,丁有骏,李明谦.有机化学.北京:北京大学出版社, 1999, 15~81
[38] Israelachvili J N. Intermolecular and surface forces. Academic Press, San Diego,1992, 9~39
[39] Ma X, Chen J, Richter JH, et al. Contribution of lubricant thickness to head-media spacing. IEEE Transactions on Magnetics, 2001, 37(4):1824~1826
[40]唐微微,孟永刚.范德华力对计算机磁头磁盘超薄气膜承载性能的影响.摩擦学学报, 2007, 27(1): 6~10
[41]张会臣,雒建斌.硬盘润滑剂性能及其对磁记录系统动力学特性的影响研究进展.摩擦学学报, 2004, 24(5): 476~482
[42] Zhang B, Nakajima A. Possibility of surface force effect in slider air bearing of 100Gbit/in2 hard disks. Tribology Intermational, 2003, 36(4): 291~296
[43] Choi D H, Kang T S. An optimization method for design of subambient pressure shaped rail sliders, Journal of Tribology, 1999, 3(1): 575~579
[44] Ross C. Patterned magnetic recording media. Annual Review of Materials Research, 2001, 31(1): 203~235