Advanced heads for perpendicular recording at high areal densities and high data rates

Liu, F.H.; Stoev, K.; Leal, L. Gary; Wang, J.; Chen, Y.; Shi, Shengjie; Tong, Ho‐Ming; Lederman, M.; Re, M.

doi:10.1109/tmag.2002.988928

Cited by 15 publications

(8 citation statements)

References 11 publications

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“…Fig. 3 shows the exact solutions of the real (open squares) and imaginary (open circles) parts of as well as their best fits represented by (3). It is clearly demonstrated that the complicated reader lumped-element circuit can be well represented by an equivalent in parallel to .…”

Section: Simplified Diagram For the Readermentioning

confidence: 93%

“…If the lumped-element reader circuit is well approximated by parallel and , then its transfer function has to be well represented by (3). Conversely, if fits well to (3), the fitting parameters , , , and can be used to extract and .…”

Section: Simplified Diagram For the Readermentioning

confidence: 99%

“…Recently, magnetic recording with areal density as high as 107 Gb/in [1] and transfer data rates of more than 1 GB/s has been demonstrated [2], [3]. Clearly, the capability to record and retrieve data quickly will be critical to the success of the next generations of hard drives.…”

Section: Introductionmentioning

confidence: 99%

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Lumped-element RC model for high-data-rate thin-film heads

et al. 2003

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We have developed a lumped-element model for a thin-film giant magnetoresistive head with an inductive writer and used it to study the effect on the data rate capability. Our work shows that the reader can be approximated well by a resistor ( e ) and a capacitor ( e ) in parallel. The paper discusses the relative importance of different contributors to e and addresses the effect of e on the spectrum of the read-back signal and the electrical reader pulsewidth (PW50) in detail. The model predictions and spin-stand data agree reasonably well. The paper also reports on our study of the amount of writer-to-reader coupling in the transducer. Our work points out the importance of minimizing the parasitic capacitance between elements in the writer and reader and avoiding direct coupling between the writer and reader leads.Index Terms-High data rate, magnetic disk storage, magnetic heads, writer-to-reader coupling.

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Section: Simplified Diagram For the Readermentioning

confidence: 93%

Section: Simplified Diagram For the Readermentioning

confidence: 99%

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Lumped-element RC model for high-data-rate thin-film heads

et al. 2003

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“…To further illustrate the recording process, arrows of flux response have also been indicated on the cross section of the head and SUL. While the size of the arrow corresponds to the magnitude of the response, the orientation of the arrow indicates the flux direction [7].…”

Section: A Basic Probe Head Design and Modelingmentioning

confidence: 99%

“…Due to the aforementioned combined advantages of SUL, the media thermal stability factor can thus be increased, since a higher writing field allows an increase in the magnetic anisotropy and a thicker layer increases the activation volume . In addition, using ring heads and perpendicular recording media with SUL, it has also been shown that ultrahigh linear densities can be achieved, thus enabling higher bit-aspect-ratio (BAR) recording systems [6], [7]. Comparing to that of ring heads, micromagnetic modeling results show that even higher write field and sharper write field gradients can be generated with probe heads (or single-pole-type heads) on perpendicular recording media with SUL.…”

Section: Introductionmentioning

confidence: 99%

Advanced probe head for perpendicular recording

et al. 2002

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Basic design and recording performance of the advanced probe heads are described. Excellent writability of the advanced probe heads is demonstrated by a series of overwrite (OW) and nonlinear transition shift (NLTS) saturation measurements. Write currents as low as 5 mA o p are required for recording. Excellent OW can be obtained with both high and low OW ratios. Media with vibrating sample magnetometry coercivities as high as 7000 Oe can be recorded with OW of 30 dB. Better than 14 dB of NLTS was measured at a linear density of 600 kfci. Minimal side-writing has been observed using the advanced probe heads with square pole shape. External field sensitivity of the advanced probe heads has also been shown to be excellent as larger than 58 Oe of external field is required to erase a low density signal on a 3380-Oe disk. Modeling results also show that the basic architecture of advanced probe head is extendible to 0.1-m square pole.Index Terms-Finite-element model, high areal density magnetic recording, perpendicular recording.

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Experimental study of playback giant magnetic resonance head nonlinearity in perpendicular recording

Luo

Stoev

Liu

et al. 2003

Journal of Applied Physics

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In this article, nonlinear distortions of the playback giant magnetic resonance ͑GMR͒ sensor in perpendicular recording are characterized in both time and frequency domains. We use three perpendicular media with different M r t ͑0.46, 0.6, and 0.8 emu/cm 2 ͒ and two groups of similar magnetic-read width ͑MRW͒ but different junction type ͓contiguous junction ͑CJ͒ and lead-over-lay ͑LOL͔͒ GMR heads. Square-wave patterns at moderate densities are recorded to minimize NLTS, partial erasure, and transition broadening effects. Both time-and frequency-domain measurements indicate that the LOL-type GMR heads show playback nonlinearity ͑7%-23%͒, while the CJ-type GMR heads do not. Micromagnetic simulation is utilized to understand the hard bias field with different junction designs. The result indicates that the hard bias ͑HB͒ field in LOL type ͑HB field ϳ6.9 Oe͒ at the air bearing surface ͑ABS͒ and stripe center is much lower than that in CJ type ͑HB field ϳ54.0 Oe͒. Therefore, the free layer with large HB-HB distance will be more susceptible to saturation.

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Advanced heads for perpendicular recording at high areal densities and high data rates

Cited by 15 publications

References 11 publications

Lumped-element RC model for high-data-rate thin-film heads

Lumped-element RC model for high-data-rate thin-film heads

Advanced probe head for perpendicular recording

Experimental study of playback giant magnetic resonance head nonlinearity in perpendicular recording

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