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Displaying 1-17 of 17 articles from this issue
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Article type: Cover
Pages Cover1-
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (16K) -
Article type: Index
Pages Toc1-
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
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Naoki HONDA, Kiyoshi YAMAKAWA, Kazuhiro OUCHI, Tatsuya KOMUKAIArticle type: Article
Session ID: MMS2010-25
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSEffect of inclination direction on the recording performance of bit-patterned media with weakly inclined anisotropy was investigated by simulation. Magnetic dots with a size of 15×7.5×5 nm^3 were arranged on a soft magnetic underlayer with an areal density of 2.6 Tdot/in^2. Saturation magnetization of each dot was assumed to be 1000 emu/cm^3. Media with three different inclination directions with an inclination angle of 30 degrees from the film normal were investigated for the recording performance using a shielded planar head field. It was found that the write shift margin in the cross track direction was increased for the medium with the inclination direction in the cross track direction. The cause of the increase was explained by the composite anisotropy of the dot elongated to the cross track direction with the shape anisotropy.View full abstractDownload PDF (914K) -
Takanori KIYA, Kazuyuki ISE, Yuji KONDO, Kiyoshi YAMAKAWA, Jun ARIAKEArticle type: Article
Session ID: MR2010-1
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWith the aim of evaluating magnetization of dot-patterned media by anomalous Hall effect, we studied on fundamental properties of Hall effect of recording media by changing thickness of Co-Pt storage layer and Ru underlayer. The thickness dependences exhibited different tendencies from that expected from the theory applied for a single sheet of ferromagnetic film. This is probably because that the current density of the storage layer changed with layer structure of the media.View full abstractDownload PDF (813K) -
Masayuki TAKAGISHI, Kenichiro YAMADA, Hitoshi IWASAKI, Hiromi Nu FUKE, ...Article type: Article
Session ID: MR2010-2
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe estimated the current perpendicular to plane (CPP)-MR performance target required for HDD with areal density from 2Tb/in^2 to 5Tb/in^2, considering spin transfer torque (STT) and thermal magnetic noise. It is found that the noise due to STT drastically affects the MR performance target for low RA film. Read elements with higher RA (around 0.1-0.3Ω・μm^2) are preferable to control STT. In addition, thermal magnetic noise remained smaller than media magnetic noise for 2Tb/in2 while it becomes comparable to media magnetic noise for 5Tb/in^2, suggesting the necessity of a new method to control thermal magnetic noise.View full abstractDownload PDF (875K) -
Yasuaki NAKAMURA, Yoshihiro OKAMOTO, Hisashi OSAWA, Hajime AOI, Hiroak ...Article type: Article
Session ID: MR2010-3
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this report, we evaluate the performance of the write-margin for the low-density parity-check (LDPC) coding and iterative decoding system in the bit-patterned media (BPM) R/W channel affected by the write-head field gradient, the media switching field distribution (SFD), the demagnetization field from adjacent islands and the island position. It is clarified that the LDPC coding and iterative decoding system in R/W channel using BPM under 2Tbit/inch^2 has a write-margin of about 20%.View full abstractDownload PDF (818K) -
M. Shiimoto, H. Katada, Y. Urakami, M. Hashimoto, M. Sugiyama, T. Ichi ...Article type: Article
Session ID: MR2010-4
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe investigated the effect of transition curvature on track edge noise through experiments and calculations. We measured and calculated two types of recording heads that had similar magnetic write widths, but different transition curvatures. In both the measurements and calculations, the track edge noise increased more at high linear density with the head with larger transition curvature, due to its wider erase band, which was considered to be noise source at the track edge. We also clarified that reducing the transition curvature was effective to increase signal-to-noise ratio (SNR), especially at high linear density, and that reducing the track edge fluctuation was effective to increase SNR, especially at low linear density. Therefore, reducing both the transition curvature and track edge fluctuation is necessary to reduce track edge noise and consequently achieve high areal density.View full abstractDownload PDF (827K) -
Kenji MIURA, Eiji YAMAMOTO, Hajime AOI, Hiroaki MURAOKAArticle type: Article
Session ID: MR2010-5
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper, the feasibility of two-dimensional magnetic recording is discussed from the viewpoint of high track density. 747 curves of shingled track were measured using existing heads and media and were interpreted with a squeezing model dominated by the SN ratio of the read head output. As long as a reader can be placed on the median line of the squeezed data area, wider OTC than that of conventional writing will result. The modeled 747 curves were in good agreement with the experimental data for both conventional writing and shingled writing. Consequently, reduction of erase band widths is important in the case of shingled writing even if the erase band width is reduced on only one side. By skewing head, reduced erase band width is accomplished.View full abstractDownload PDF (801K) -
Terumasa AOKIArticle type: Article
Session ID: MR2010-6
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper., principles, history and technical trends of next-generation digital content such as 3D video and the five-sense content are summarized and the requirements for recording media to handle these kinds of content are described.View full abstractDownload PDF (1425K) -
Ryuji SUGITA, Takashi KOMINEArticle type: Article
Session ID: MR2010-7
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSServo signals can be written with incredibly high speed compared to conventional methods, high accuracy and low cost by using a magnetic printing method. There are two types of magnetic printing for perpendicular hard disks. One is bit printing where printing magnetic field is applied in perpendicular direction, and the other is edge printing where the field is applied in in-plane direction. The merit of the bit printing is that the reproduced waveform from printed hard disks is almost the same as that from head-recorded ones. On the other hand, in the edge printing high S/N is expected in short bit length region. It is possible to magnetic-print the bit below 50nm long, which shows the perpendicular magnetic printing is usable for ultrahigh density hard disks such as 1Tb/in^2 or more.View full abstractDownload PDF (1334K) -
Kinya FUDANO, Hiroaki Muraoka, Yoshihisa NAKAMURAArticle type: Article
Session ID: MR2010-8
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSConsideration of the demagnetizing field in a recording medium is important to determine the optimum conditions for the write field. The effect of the magnetic interaction between a write head and a medium has to be taken into account to obtain an accurate description of the recording process in perpendicular magnetic recording. In this study, a detailed analysis of the effect of the demagnetizing field on the recording process was performed using a finite-element method (FEM) computer simulation of heads and media. The simulator was combined with a Stoner-Wohlfarth magnetization reversal model, in which head-medium magnetic interactions were incorporated by calculating the head and medium magnetization together as a 'self-consistent' system, designated as "SMART". Using this simulator, the demagnetizing field in a recording layer located between a main pole and soft magnetic underlayer (SUL) was calculated for various combinations of heads and media. So the optimum condition for the write head and medium could be lead by calculating the demagnetization factor accurately with this simulator for the high-density perpendicular magnetic recording.View full abstractDownload PDF (1122K) -
Koji TSUSHIMA, Kenji MIURA, Hajime AOI, Hiroaki MURAOKAArticle type: Article
Session ID: MR2010-9
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn order to achieve high linear density recording, estimating magnetization distribution of recorded magnetization transition is required. In this work, we calculated detailed magnetization distribution from measured waveform and calculated sensitivity function by using Jacobi iteration. As a result, valid transition distributions were obtained.View full abstractDownload PDF (785K) -
Masato YAMASHITA, Hisashi OSAWA, Yoshihiro OKAMOTO, Yasuaki NAKAMURAArticle type: Article
Session ID: MR2010-10
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe neuro-interpolator (NI) integrating an interpolator with a neural network equalizer in holographic data storage is proposed to reduce the influence of interpixel interference due to the aperture restriction which limits the effective recording area on the holographic medium. The simplification of NI is performed by using a hybrid genetic algorithm based on a new mutation method introducing a pruning probability, and its bit error rate (BER) performance is studied by computer simulation. The results show that the BER performance of simplified NI is superior to that of the interpolator alone. Furthermore, the number of connections in the simplified NI is reduced to about half of that obtained by using a conventional mutation method. In addition, the proposed mutation method shows the slightly-improved performance over the conventional one.View full abstractDownload PDF (773K) -
Jyunya YAMASHITA, Yoshihiro OKAMOTO, Yasuaki NAKAMURA, Hisashi OSAWA, ...Article type: Article
Session ID: MR2010-11
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe iterative decoder is composed of APP (a posteriori probability) decoder using the characteristics of PR (partial response) channel and SP (sum-product) decoder using the check matrix of LDPC (low density parity check) code. As the jitter-like medium noise is dominant in perpendicular magnetic recording, APP decoder regarding the jitter-like noise is required. In this paper, the parameter setting of APP decoder is studied regarding the influence of jitter-like medium noise. The required SNR to decode 1Mbit of sequence without error is obtained by computer simulation, and the results show that SNR improves about 0.6dB.View full abstractDownload PDF (766K) -
Article type: Appendix
Pages App1-
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (100K) -
Article type: Appendix
Pages App2-
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (100K) -
Article type: Appendix
Pages App3-
Published: June 10, 2010
Released on J-STAGE: September 21, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (100K)
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