Thermal pole-tip protrusion analysis of magnetic heads for hard disk drives

Aoki, Kenichiro; Hoshino, Tsutomu; Iwase, T.; Imamura, Takako; Aruga, K.

doi:10.1109/intmag.2005.1464378

Cited by 4 publications

(6 citation statements)

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“…Among the technologies enabling sliders to fly lower, the thermal flying-height control (TFC) technology has become the most popular one [1,2]. As illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

Effects of Altitude on Thermal Flying-Height Control Actuation

et al. 2010

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Thermal flying-height control (TFC) is now a key technology used in hard-disk drives (HDD) as an effective way to push the magnetic spacing to sub-5 nm. Precise control of the TFC sliders' actuated flying-height (FH) is a major consideration in improving the read/write capability as well as reducing the reliability problem. In this paper, we investigate the response of TFC sliders to altitude changes with a focus on the variation of actuated FH. Numerical and experimental results both indicate an increase in the actuated FH at higher altitudes. Simulations show that the increased TFC protrusion and less air bearing pushback on sliders at higher altitudes contribute to this increase. This study is of practical importance for improving heater and air bearing surface design to reduce the TFC sliders' sensitivities to altitude changes.

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“…Among the technologies enabling sliders to fly lower, the thermal flying-height control (TFC) technology has become the most popular one [1,2]. As illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

Effects of Altitude on Thermal Flying-Height Control Actuation

et al. 2010

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“…Write current-induced Pole-Tip Protrusion (W-PTP) is caused by the joule loss of write coil. Many researches have clarified the mechanism of the deformations [1]- [6].…”

Section: Introductionmentioning

confidence: 99%

Nonlinearity of Thermal Spacing Control in Hard Disk Drives

Aoki

Watanabe

2009

IEEE Trans. Magn.

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Thermal spacing control using a heater in a magnetic head has been a key technology for achieving lower magnetic spacing. However, spacing change is nonlinear to the heating power, and the relationship between the heating power and the spacing change in low spacing region is very important to clarify. We numerically evaluated spacing change focusing on the effect of heating power. The numerical results were verified by comparing with experimental results. By coupling Reynolds equation and heater-induced pole-tip protrusion (H-PTP), numerical results agreed well with experimental results. Using the numerical model, we found the H-PTP shape difference due to the heat transfer change rarely influences the spacing change, and the height of H-PTP significantly affects the spacing change. Also, we clarified that the nonlinearity is significantly influenced by the lowest spacing and the initial pressure at the maximum H-PTP area. This knowledge is the key for a design of spacing control by a heater.Index Terms-Finite-element method, head-disk interface, thermal pole-tip protrusion, thermal spacing control.

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“…The current flying height is approximately around 5 nm. At a low head-disk clearance, variations of the flying height for a nanometer have an influential effect on the recording performance [1]. A tolerance stack-up in manufacturing processes and the head protrusion induced by ambient temperature and write current can generate the flying height variations.…”

Section: Introductionmentioning

confidence: 99%

“…A tolerance stack-up in manufacturing processes and the head protrusion induced by ambient temperature and write current can generate the flying height variations. To achieve the target head-media clearance during writing and reading processes, a slider that consists of a heater near the read/write elements is applicable for adjusting the head-media clearance [1][2][3][4][5]. The heating generated in the heater induces head deformation called heater-induced head protrusion (H-IHP).…”

Section: Introductionmentioning

confidence: 99%

A study of head instabilities in TMR sensors using in high density perpendicular magnetic recoding systems

Tongsomporn¹,

Afzulpurkar

Sitthisak

2009

JAE

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We did an experimental study to examine head instabilities and noise of tunneling magnetoresistance (TMR) sensors using in high-density perpendicular recording systems. It found that the instability signatures on the transfer curves could be categorized into two groups; permanent magnet/free layer (PM/FL) failure and synthetic antiferromagnetic layers/antiferromagnetic layer (SAF/AFM) failure. The thermal-mechanical stress from the adaptive flying height (AFH) heater as well as head-disk interaction potentially degrades PM resulting in the reduction of the FL stabilizing field, therefore TMR ratio and signal increases. The non-uniformity of PM remnant magnetization and the switching of PM grains especially near the edge potentially degrade the biasing field. Scanning electron microscope images of these weak heads show rough surface and scratches close to the active area of read sensor. The deep scratches by particles in the head-disk interaction and shallow scratches by the slider lapping process is a potential cause to degrade PM. In another group, the thermal-mechanical stress from AFH heater potentially reduces the exchange-bias field and thermal stability of SAF/AFM layers allowing partial flipping of SAF edge magnetization, consequently it induces voltage fluctuations and hysteresis loops in the transfer curves.

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Thermal pole-tip protrusion analysis of magnetic heads for hard disk drives

Cited by 4 publications

References 0 publications

Effects of Altitude on Thermal Flying-Height Control Actuation

Effects of Altitude on Thermal Flying-Height Control Actuation

Nonlinearity of Thermal Spacing Control in Hard Disk Drives

A study of head instabilities in TMR sensors using in high density perpendicular magnetic recoding systems

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