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Article type: Cover
Pages Cover1-
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (13K) -
Article type: Index
Pages Toc1-
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (64K) -
T. K. Byun, K. K. Kim, Y. Oh, C. S. Yoon, C. K. KimArticle type: Article
Session ID: MMS2002-69
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe segregation of non-magnetic phases such as borosilicate and Cr was investigated by crystallization behavior durin g the surface and bulk crystallization of Co-based amorphous alloys. The concentration of metalloids (B and Si) determined the extent of grain boundary segregation of borosilicate glass during surface crystallization. During the bulk crystallization of paramagnetic (Co_<75>Cr_<25>)_<0.8>Si_5B_<15> amorphous alloy, solute rejection of Cr resulted in the nucleation of Cr-deficient ferromagnetic crystals and σ -phase was subsequently precipitated along the grain boundary. These results shows that crystallization process, i. e. nucleation and growth can be controlled to optimize the microstructure to reduce noises in Co-based recording mediaView full abstractDownload PDF (585K) -
Hirofumi WADA, Setsuo YAMAMOTO, Hiroki KURISU, Mitsuru MATSUURA, Yoshi ...Article type: Article
Session ID: MMS2002-70
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSA novel reactive sputtering method using an Electron-Cyclotron-Resonance (ECR) microwave plasma was used to deposit Ni-Zn ferrite thin-films for a soft magnetic backlayer of Co-containing spinel ferrite thin-film perpendicular magnetic recording media. To achieve high deposition rate, configuration of sputtering target, position of oxygen gas inlet and processing parameters such as microwave input power, target voltage, oxygen partial pressure were carefully optimized. Ni-Zn spinel ferrite thin-films with preferential orientation of (400) and relatively low coercivity of 15 Oe were obtained at a high deposition rate of 14 nm/min and at a temperatures lower than 200 degrees C. The reactive ECR sputtering is one of the most suitable preparation methods of ferrite thin-films applicable to the perpendicular magnetic recording media.View full abstractDownload PDF (461K) -
Hirofumi KUNIKI, Setsuo YAMAMOTO, Hiroki KURISU, Mitsuru MATSUURAArticle type: Article
Session ID: MMS2002-71
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSCo-containing ferrite thin-film / Mn-Zn ferrite thin-film double-layer perpendicular media were prepared using reactive ECR sputtering and magnetron sputtering methods, and their magnetic and structural properties and recording characteristics were studied. Mn-Zn ferrite thin-film backlayer had saturation magnetization of 3.5 kG and coercivity of 60 Oe. Reproduced voltage for the Co-containing ferrite thin-film / Mn-Zn ferrite thin-film double-layer medium was about twice of that for the Co-containing ferrite single-layer medium.View full abstractDownload PDF (771K) -
Y. G. Ma, Z. Yang, F. L. Wei, M. Matsumoto, A. Morisako, S. TakeiArticle type: Article
Session ID: MMS2002-72
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe effects of magnetic layer thickness and boron addition on the microstructure and magnetic properties of NdFeB thin films sputtered onto W underlayer have been investigated. The films could maintain prominent perpendicular magnetic anisotropy when their thickness values were smaller than 30 nm. Beyond this value, the c-axis orientations of magnetic grains became irregular gradually. Moderate boron addition could effectively suppress grains growth and narrow grain size distributions as well as tailor the high coercivity force to an applicable value while keeping a relative high remanent ratio. The grains also became more isolated.View full abstractDownload PDF (351K) -
M. F. Chiah, P. Chen, H. Wang, W. Y. Cheung, N. Ke, C. Y. Poon, Z. S. ...Article type: Article
Session ID: MMS2002-73
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSCoPt-C, FePt-C and PrCo-C nanocomposite thin this films were prepared by a pulsed filtered vacuum are deposition technique. Vacuum thermal annealing and rapid thermal annealing were performed at various temperatuers. The dependence of the magnetic properties on the carbon fraction and annealing temperatuer was studied. For the film with a particular composition of Fe_<43>Pt_<35>C_<22>, the coercivity and the grain size were observed to increase with increasing annealing temperature, up to a vlue of 3.5 kOe at an annealing temperature of 650℃, and with a grain size about 10.5 nm. For the sample of (Pr_<0.17>Co_<0.83>)_<69>C_<31> annealed at 700℃ for one minute, it showed a large coercivity of 5.2 kOe and a small grain size of 7.8nm. The overall small negative ΔM of this film indicated that virtually all the Pr_<0.17>Co_<0.83> grains were isolated single domain particles with only weak dipolar interactions among them. These results indicated that these nanocomposite thin films would be promising candidates for high-density magnetic recording medium applications.View full abstractDownload PDF (570K) -
Yoshitaka KITAMOTO, Hiroshi SAKUMA, Hiroki ITOH, Yohtaro YAMAZAKI, Hir ...Article type: Article
Session ID: MMS2002-74
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSNanparticles of FePt were fabricated by two types of solution process. One is thermal decomposition and reduction of organometallic compounds in an organic slovent, and the other is reduction of metl ions in reversed micelles based on an aqueous solutiion process. In either way, mondisperse FePt prticles of about 3nm are fourmed. Self-assembly was observed in case of the particles fabricated by the former method, while in case of the latter method, self-assembly was not observe. The maximum diameter of particles in assembled film increased up to 10nm by annealing. Magnetic evaluation in the from of powder showed that atomic ordering of Fe and Pt in L1_0 structure strongly influenced coercivity and magnetization decay.. It is necessary to improve the accuracy for magnetic measurements of very thin assembly-films since their magnetization is too small.View full abstractDownload PDF (622K) -
Jian Qin, Dan WeiArticle type: Article
Session ID: MMS2002-75
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSA combined theory of the micromagnetic and Monte Carlo simulations is established to analyze the thermal property of a nano-sized magnetic grain. The Langevin equation of a grains's magnetic moment is the Landau-Lifshitz equation augmented by a "random-field" term representing the thermal-agitated force. The angular distribution of the magnetic moment of the grain is studied via its time evolution process. The tunnelling of the magnetic moment vector between two energy-minimum states is observed. A simple analytical expression is obtained for the simulated attempt frequency, which agrees well with the experiential value.View full abstractDownload PDF (354K) -
Takashi KOMAKINE, Naoki HONDA, Kazuhiro OUCHIArticle type: Article
Session ID: MMS2002-76
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIntegrated noise power for double-layered perpendicular magnetic recording media was experimentally observed as increasing with the transition density at relatively low densities while saturating at a higher density. First, a noise model with a finite transition width was analyzed assuming the transition jitter was the dominant source of the medium noise. Though the calculated noise power increased with increasing the transition density at relatively low densities, it reduced at higher densities as different from the experimental data due to the decrease in the recorded magnetization by the inter-transition-interference at the bit crowded situation. Decrease in the magnetization level of the medium should result in increase of reversed domains, so that the reversed domain noise increases when the transition density increases. Therefore, the experimental result that the medium noise saturated at higher transition densities could be explained as a summation of the decreased jitter noise and the increased reversed-domain noise giving a constant value. The noise power at the extreme density should represent to the AC-erased noise power. The dependence of the jitter noise properties on the transition density for the bit crowded situation will be discussed both in perpendicular and longitudinal recording.View full abstractDownload PDF (620K) -
S. C. Lee, Y. W. Tahk, K. J. Lee, T. D. LeeArticle type: Article
Session ID: MMS2002-77
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this work, micromagnetic simulations of writing and reading processes in a perpendicular system including a single pole head and a recording medium with soft underlayer (SUL) have been performed. The noise contribution from the recording layer increased with increasing grain size distribution of the recording layer but that from soft undelayer remained almost a constant at a given linear density. Details of the noise form the soft underlayer will be discussed. Also thermal decay over a long time scale of the recorded bits was investigated by the Langevin equation and the time-temperature scaling method. It was found that at the linear density of 1058 kfci, narrower grain size distribution in the recording layer is very important in the point of thermal decay than expectationView full abstractDownload PDF (517K) -
Weichun Ye, Huijie Cao, Yu LinArticle type: Article
Session ID: MMS2002-78
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe performances of three transition response models used in perpendicular magnetic recording channel were compared and analyzed. Based on the study results, three modified transition response models with an exponential term 'K' added to the conventional models were proposed that match better with the actual response. An analytically derived response was used as the reference for comparison with the waveform obtained from the model. The optimum value of the index 'K' is implemented to minimize the fitting error. Simulation results indicate that the modified models with addition of index 'K' which gave smaller fitting error were superior to the popular models. The performances of modified hyperbolic tangent and modified error function models are better than that of modified arctangent model. Also, the modified hyperbolic arctangent model seems easier to implement for simulation and evaluation of channel performance because of its simplicity. The effects of GMR head and double layered media with different geometric and magnetic parameters on the readback pulse shape were also investigated. The study results indicate that a model with optimal 'K' could be used to evaluate the system performance for a particular head-media combination.View full abstractDownload PDF (662K) -
Xiaobing Liang, Dan WeiArticle type: Article
Session ID: MMS2002-79
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSA series of micromagnetic models are utilized to study the recording performance in hard disk driver (HDD) at extremely high densities, including simulations of the 3D thin film write head field, the GMR read head, the thin film media and channel codes. By these models the read & write process in longitudinal magnetic recording media of HDD are analyzed. The (0, 4/4) encoder and the corresponding decoder are utilized to translate the user data into (0, 4/4) constrained codes, before the write process is performed. The write current is achieved from the constrained code in the NRZ format. The read back voltage is equalized to PR-IV signal and the viterbi detector is utilized to recover the data. In a medium of 10 nm grains, the recordingdensity limits with PRML method are about 1000 kfci, which is 1.5 times of those with PD method, indicating that PRML is an useful approach to improve the read back properties of HDD>View full abstractDownload PDF (484K) -
Article type: Appendix
Pages App1-
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (74K) -
Article type: Appendix
Pages App2-
Published: November 07, 2002
Released on J-STAGE: September 20, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (74K)
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