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Article type: Cover
Pages Cover1-
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (14K) -
Article type: Index
Pages Toc1-
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (89K) -
Yukio HONDA, Yoshiyuki HIRAYAMA, Atsushi KIKUKAWA, Masaaki FUTAMOTOArticle type: Article
Session ID: MMS2001-69
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe effects of an intermediate layer of carbon on the structural and magnetic properties of a CoCrPtTa recording layer were investigated in double-layered perpendicular media with either amorphous CoTaZr or crystalline FeAlSi as soft magnetic backlayers. introducing a thin layer of carbon enhanced the perpendicular magnetic anisotropy with both soft magnetic backlayers. This result suggests that the introduction of a non-magnetic intermediate layer is useful in improving the basic magnetic properties of the CoCr-alloy recording layer even when an amorphous soft magnetic backlayers is used.View full abstractDownload PDF (1116K) -
shigeki Nakagawa, Atsushi Sato, Sok-Hyun Kong, Masahiko NaoeArticle type: Article
Session ID: MMS2001-70
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSPt/Ti composite underlayer has been investigated for Co-Cr-Ta perpendicular magnetic recording media. The Co-Cr-Ta/Pt/Ti trilayered films exhibited more excellent c-axis orientation and higher perpendicular coercivity than Co-Cr-Ta/Pt and Co-Cr-Ta/Ti bilayered films. In order to decrease grain size in Co-Cr-Ta films, 5 nm-thick Pt interlayer was introduced to compose [Co-Cr-Ta/Pt]_n multilayers. It was found that the Pt interlayer was effective to obtain small Co-Cr-Ta particles without decrease of perpendicular coercivity.View full abstractDownload PDF (447K) -
Takashi KOMAKINE, Naoki HONDA, Takanori KIYA, Kazuhiro OUCHIArticle type: Article
Session ID: MMS2001-71
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSNoise sources in double-layered perpendicular magnetic recording media were investigated. Though the transition jitter noise is the dominant noise in the double-layered media, the other transition noise source which originated from the reversed magnetic domains at the transitions is proposed in this paper. The MFM image and simulation results at magnetization transitions for a weak exchange-coupled medium, show the reversed domains intensivcly at the magnetization transitions. This reversed-domain-originated transition noise also increases in proportion to the recording density. The noise could be modeled as the noise burst model in which the random noise was concentrated at transitions, and should have the broader spectrum than that of the transition jitter.View full abstractDownload PDF (554K) -
Kei HIRATA, Setsuo YAMAMOTO, Hiroki KURISU, Mitsuru MATSUURA, Takanori ...Article type: Article
Session ID: MMS2001-72
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSCo-containing ferrite thin-film media deposited by a reactive-ECR-sputtering depositing ferrite thin-film at the low substrate temperature of 150 degree Celsius were oxidized by two methods. In the Co-containing ferrite thin-film medium oxidized by ECR plasma, the magnetic properties and recording characteristics were improved with maintaining a smooth surface. The medium showed high D_<50> as high as that of a commercial 20 Gb/in^2 longitudinal hard disk in MIG head recording and reproduction.View full abstractDownload PDF (712K) -
Dong-Huan Qin, Mei Lu, Hu-Lin LiArticle type: Article
Session ID: MMS2001-73
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSHighly pattern anodic aluminum oxide(AAO)was prepared by two steps anodic process. Uniform arrays of Co, Fe, Ni, CoNi and CoPt alloy nanowires were fabricated by electrochemical deposition. The micrographies and crystalloid structures of nanowires were studied by TEM, SEM, AFM and XRD. The magnetic properties were investigated by Mossbauer Spectrum(MS), Vibrating Sample Magnetometer and MFM. It was found that in the case of single metal nanowire arrays, the squareness(Mr/Ms)and coercivity of the hysteresis was very high when the external field was applied perpendicular the sample, which showed strong perpendicular anisotropy. XRD and Mossbauer show that preferred orientation existed in the case of Fe or Co nanowires. The magnetic properties were very complicate in alloy nanowire arrays. MFM results show that patterned single-domain structure existed in magnetic nanowire arrays with small diameter. The recording density could be as high as 100Gbit/cm^2 if each single-domain element represents a bit of binary information, which was very attractive in highly density recording.View full abstractDownload PDF (606K) -
Dan WeiArticle type: Article
Session ID: MMS2001-74
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSPatterned magnetic media are promising recording media for the computer hard disk to go beyond the density of 100Gb/in^2. A micromagnetic simulation model is set up to study the magnetic property as well as the recording process in patterned media. The patterned medium studied in this paper is an array of pillar magnetic particles with a perpendicular anisotropy. A pole record head as well as a thin film head are utilized in the simulated recording process. The diameter of the magnetic pillars is chosen as 20nm, the bit length takes the values of 30nm. 40nm and 50nm, with respect to an ideal areal density of 258Gb/in^2, 459Gb/in^2 and 717Gb/in^2. The magnetic signal and noise recorded in a series or patterned media are analyzed at different recording densities with the two types of record heads.View full abstractDownload PDF (472K) -
Eng Wei SOO, Weiwei JIANG, Lianjun WU, J.P. WANGArticle type: Article
Session ID: MMS2001-75
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe effect of NiP as seed layer for the[Co/Pd]_n multilayer perpendicular recording media with a new proposed FeCoC soft underlayer was studied. It was found that a thin layer of 2 nm NiP inserted between the FeCoC soft magnetic underlayer and the[Co/Pd]_n recording layer improved the magnetic properties such as coercivity, squareness and nucleation field. These improvements may be due to the enhanced grain isolation promoted by NiP seed layer, as well as the lower surface roughness of NiP seed layer. Read/wrie test was performed using a ring type head by a Guzik spin stand. The magnetic patterns recorded up to 390 kFCI for[Co/Pd]_n media with NiP seed layer can be observed clearly by magnetic force microscope images.View full abstractDownload PDF (1228K) -
M. Futamoto, K. Terayama, K. Sato, Y. Hirayama, Y. HondaArticle type: Article
Session ID: MMS2001-76
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSSingle-crystal thin films of Co-alloy materials with hcp-crystal structure are prepared on oxide single crystal substrates. The orientation of easy magnetization axis(c-axis in hcp-crystals structure)can be controlled either parallel or perpendicular to the film plane by selecting the crystallographic orientation of the substrate. The epitaxial relationship between the magnetic layer, the underlayer, and the substrate are determined. The microstructures of magnetic thin films are investigated by using a high-resolution transmission electron microscope. Using these single crystal thin films, important basic magnetic properties like magneto-crystalline anisotropy constants(Ku)can be determined.View full abstractDownload PDF (864K) -
S.C. Oh, Y.W. Tahk, T.D. LeeArticle type: Article
Session ID: MMS2001-77
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe magnetic properties and thermal stability of AFC media with thin Co interlayers are investigated. Since thermal stability is strongly dependent on the exchange coupling constant J_<ex> in the AFC media, the thin Co interlayers were inserted on both interfaces of the Ru layer to obtain higher values of J_<ex>. The J_<ex> above 0.6 erg/cm^2 was obtained in the AFC media with the Co interlayers above 1 nm in comparison with about 0.1 erg/cm^2 in the conventional AFC media without the Co interlayers. From micromagnetic simulation results, it was observed that the AFC media with the Co interlayers had higher thermal stability behavior than the AFC media without Co interlayer.View full abstractDownload PDF (362K) -
Y.W. Tahk, K.J. Lee, T.D. LeeArticle type: Article
Session ID: MMS2001-78
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSAFC media with varying antiferromagnetic(AF)coupling constant J, anisotropy constant and thickness of the stabilizing were simulated. The effects of the parameters on SNR and thermal stability were studied. It was found that the media with strong AF exchange bias field have the enhanced SNR characteristics and the media with the higher t_2 of the stabilizer layer have the lowered signal decay when Ku_2・t_2 are set to be constant to have similar kink coercivity.View full abstractDownload PDF (481K) -
J.P. Wang, S.N. Piramanayagam, C.H. Hee, L. Huang, S.I. Pang, T.C. Cho ...Article type: Article
Session ID: MMS2001-79
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSExperimental and micromagnetic simulation studies show that laminated antiferromagnetically coupled(LAC)media can push the areal density beyond 100 Gbit/in^2. A technique is shown to obtain exchange-coupling constant as high as 0.32 erg/cm^2, which is three-four times higher than the reported values in literature. This technique can improve the thermal stability factor by more than 40%. A new type of sandwich three-layer configuration for the antiferromagnetic coupled media is also proposed for the first time which may double the antiferromagnetic coupling effect for the recording CoCrPtB layer. It can also further reduce the M_rδ value(less than 0.2 memu/cm^2)while keeping a high thermal stability that may be preferred for future applications, once extremely high-sensitive read heads appear in future. Micromagnetic simulation with 3D head field has been done for this kind of media. 200 Gbit/in^2 areal density has been simulated using an orientation ratio of 2 for this kind of media.View full abstractDownload PDF (746K) -
M.F. Chiah, H. Wang, C.Y. Poon, W.Y. Cheung, S.P. Wong, A.B. Pakhomov, ...Article type: Article
Session ID: MMS2001-80
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSCoPt-C nanocomposite thin films of various carbon compositions were prepared by a pulsed filtered vacuum arc deposition technique. Annealing was performed in vacuum for one hour at various temperatures. The dependence of the magnetic properties on the carbon composition and annealing temperature was studied. Both x-ray diffraction and magnetic force microscopy analyses confirmed the formation of nano-crystallites of face-centered-tetragonal CoPt phase in the carbon matrix after annealing at a sufficiently high temperature, depending on the carbon composition. For the film with a particular composition of Co_<24>Pt_<31>C_<45> the coercivity and the grain size were observed to increase with increasing annealing temperature, up to a value of 7 kOe at an annealing temperature of 750℃, and the grain size increased from 9 to 20 nm.View full abstractDownload PDF (449K) -
Wei Qing Li, H. Wang, L. Hu, G.R. Zhou, S. Wu, M.F. Chiah, C.Y. Poon, ...Article type: Article
Session ID: MMS2001-81
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper, magnetic properties of Co-C and CoPt-C nanogranular films are modeled using the Monte Carlo method. Each grain in the films is assumed to be spherical in shape, with a single domain and a random crystalline easy axis in the model. For Co-C films, the hysteresis loop for hexagonal close-packed(hcp)Co grains of 3 nm in size is calculated at various temperatures ranging from 3 K to 300 K. The superparamagnetic relaxation blocking temperature(T_B)is demonstrated to be about 20 K. For CoPt-C films, hysteresis magnetization calculations are performed on face-central-tetragonal(fct)CoPt inter-metal compound grains encapsulated in carbon with various grain sizes ranging from 4 nm to 6 nm and different distributions. Extremely high coercivities required by ultra-high density magnetic recording are achieved in these films owing to the very large anisotropy of fct CoPt compound. The numerical results are compared with our experimental data of Co-C granular films and those of CoPt-C granular films recently reported in the literatures.View full abstractDownload PDF (376K) -
Jian Li, Xiaobing Liang, Dan WeiArticle type: Article
Session ID: MMS2001-82
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe write density limit is explored by analyzing the magnetic recording process in computer hard disk drives with a micromagnetic model. The digital data with random sequences are recorded in longitudinal media at different densities. A novel method has been utilized to study the write density limit: the simulated read back voltage and the respected superlinearposed isolated pulses are compared to find the distortion in the record process. When a severe distortion shows up, the corresponding areal density is considered as the write density limit. By the novel method, the write density limit is analyzed with different parameters of the thin film write head, the GMR read head and the thin film media.View full abstractDownload PDF (431K) -
Jie FengArticle type: Article
Session ID: MMS2001-83
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIt is necessary to compensate for the demagnetizing field in remanence measurements of perpendicular magnetic recording films. In this paper, a new method of compensating for the demagnetizing field is proposed and an effective reverse field H_<eff> is used to evaluate the dc demagnetization measurements, isothermal remanent magnetization curves, and the ΔM plots for perpendicular magnetic recording films. The demagnetization factor N is important for this method, and three methods are used to estimate the value of N. The results of the ΔM plots indicate that the intergranular interactions in Ba ferrite films seem to be exchange coupling, while those in Co-Cr-Ta films are magnetostatic interactions.View full abstractDownload PDF (465K) -
J. Bai, Z. Yang, F. Wei, M. Matsumoto, A. MorisakoArticle type: Article
Session ID: MMS2001-84
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe magnetic and structural properties of the FePt and FePt-Al_2O_3 films were investigated. In the FePt films, the relationship between the enhancement of coercivity and the phase transition from fcc to fct structure was discussed. It is believed that high coercivity of the films arose from the fully chemical LRO(Long Range Ordered)structure of FePt. As for the 550℃-annealed FePt-Al_2O_3(25vol%)films, the influences of film thickness on the magnetic and structural properties were examined. All results showed the feasibility of FePt-Al_2O_3 films for ultrahigh density magnetic recording.View full abstractDownload PDF (429K) -
Article type: Appendix
Pages App1-
Published: November 07, 2001
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (86K)
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