Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565914
Provides a listing of current staff, committee members and society officers.
提供现有工作人员、委员会成员和社会官员的名单。
{"title":"[Masthead]","authors":"","doi":"10.1109/TJMJ.1994.4565914","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565914","url":null,"abstract":"Provides a listing of current staff, committee members and society officers.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"nil1-nil1"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565914","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565920
H. Okuno;T. Homma
Chaotic oscillation of a domain wall is demonstrated by computer simulations based on a differential equation which includes terms for the nonlinear force of restitution and eddy current damping. Chaotic oscillation involves irregular phenomena (the error or noise in magnetic recording systems) and energy losses. Bifurcation diagrams of magnetic domain-wall motion is a useful method for investigating chaotic behavior. The external magnetic field is an important parameter in the design of magnetic devices. The bifurcation diagram of the wall velocity is calculated for the amplitude of the external magnetic field. The route to chaos is through bifurcation via periods 2, 3, 4 and 5 from period-1 oscillation. The periodic windows and chaotic regions appear in alternation. The energy loss caused by the domain wall motion was calculated; the value of the energy loss in chaotic motion is larger than that for regular motion, despite their having the same damping coefficient. Chaotic motion is thus a new mechanism causing increases in the energy loss.
{"title":"Bifurcation Diagram and Energy Loss of Chaotic Domain-Wall Motion","authors":"H. Okuno;T. Homma","doi":"10.1109/TJMJ.1994.4565920","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565920","url":null,"abstract":"Chaotic oscillation of a domain wall is demonstrated by computer simulations based on a differential equation which includes terms for the nonlinear force of restitution and eddy current damping. Chaotic oscillation involves irregular phenomena (the error or noise in magnetic recording systems) and energy losses. Bifurcation diagrams of magnetic domain-wall motion is a useful method for investigating chaotic behavior. The external magnetic field is an important parameter in the design of magnetic devices. The bifurcation diagram of the wall velocity is calculated for the amplitude of the external magnetic field. The route to chaos is through bifurcation via periods 2, 3, 4 and 5 from period-1 oscillation. The periodic windows and chaotic regions appear in alternation. The energy loss caused by the domain wall motion was calculated; the value of the energy loss in chaotic motion is larger than that for regular motion, despite their having the same damping coefficient. Chaotic motion is thus a new mechanism causing increases in the energy loss.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"27-33"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565920","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565927
K. Takano;Y. Nakamura
The linear recording density in perpendicular magnetic recording is limited by the thickness of the main-pole in the single-pole head. In order to raise the practical readback resolution, a thin main-pole film is indispensable. Fe-Si film has a large saturation magnetization and good soft magnetic properties are obtained at thicknesses between 50 and 200 nm. However, as the film thickness decreases below 100 nm, the domain wall structure and domain configuration change from Bloch-type walls and closure domains. A head with such a thin film as its main-pole has unstable readback output and poor resolution. The authors therefore adopted as the main-pole an Fe-Si/SiO 2 multi-layered film whose domain structure differs from that of a single-layer Fe-Si film. As a result, the output stability and high-density response could be improved by controlling the intermediate layer (hereafter "inter-layer") thickness and the number of magnetic layers.
{"title":"Single-Pole Heads with Thin Fe-Si Main-Pole Films","authors":"K. Takano;Y. Nakamura","doi":"10.1109/TJMJ.1994.4565927","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565927","url":null,"abstract":"The linear recording density in perpendicular magnetic recording is limited by the thickness of the main-pole in the single-pole head. In order to raise the practical readback resolution, a thin main-pole film is indispensable. Fe-Si film has a large saturation magnetization and good soft magnetic properties are obtained at thicknesses between 50 and 200 nm. However, as the film thickness decreases below 100 nm, the domain wall structure and domain configuration change from Bloch-type walls and closure domains. A head with such a thin film as its main-pole has unstable readback output and poor resolution. The authors therefore adopted as the main-pole an Fe-Si/SiO\u0000<inf>2</inf>\u0000 multi-layered film whose domain structure differs from that of a single-layer Fe-Si film. As a result, the output stability and high-density response could be improved by controlling the intermediate layer (hereafter \"inter-layer\") thickness and the number of magnetic layers.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"72-79"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565927","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565937
M. Kubogata;M. Ogawa;M. Nakada;O. Okada
Optical enhancement conditions and read/write characteristics for exchange-coupled double-layer magnetooptic (MO) disks were investigated. It was found that the figure of merit (R (1/2) ·θ K ) for an MO disk with a thick (60 nm) magnetic layer is comparable to that of a conventional MO disk with a thin (20 nm) magnetic layer. The write noise level of the thick-magnetic-layer MO disk is markedly lower (2 to 5 dB) than that of the conventional disk. An exchange-coupled double-layer (GdFeCo 30 nm/TbFeCo 30 nm) MO disk, with a large Kerr rotation, moderate reflectivity and low noise level, is suitable for use as a high-performance medium. This MO disk has a C/N ratio of 45 dB at a wave-length of 680 nm, and a mark length of 0.67 pm when polycarbonate substrate with a track pitch of 1.2 μm is used.
{"title":"Exchange-Coupled Double-Layer Magneto-Optical Disk with a Reflecting Layer","authors":"M. Kubogata;M. Ogawa;M. Nakada;O. Okada","doi":"10.1109/TJMJ.1994.4565937","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565937","url":null,"abstract":"Optical enhancement conditions and read/write characteristics for exchange-coupled double-layer magnetooptic (MO) disks were investigated. It was found that the figure of merit (R\u0000<sup>(1/2)</sup>\u0000·θ\u0000<sub>K</sub>\u0000) for an MO disk with a thick (60 nm) magnetic layer is comparable to that of a conventional MO disk with a thin (20 nm) magnetic layer. The write noise level of the thick-magnetic-layer MO disk is markedly lower (2 to 5 dB) than that of the conventional disk. An exchange-coupled double-layer (GdFeCo 30 nm/TbFeCo 30 nm) MO disk, with a large Kerr rotation, moderate reflectivity and low noise level, is suitable for use as a high-performance medium. This MO disk has a C/N ratio of 45 dB at a wave-length of 680 nm, and a mark length of 0.67 pm when polycarbonate substrate with a track pitch of 1.2 μm is used.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"139-143"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565937","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565925
K. Nakamoto;H. Fukui;T. Iwakura;T. Ohtsu
The read-write characteristics of thin-film heads with a NiFe/CoNiFe laminated upper pole were studied. Compared with NiFe heads, NiFe/CoNiFe laminated heads are better able to suppress loss of output and increases in disk noise, and provide better overwrite characteristics. Comparison of experimental and calculated results indicate that pole saturation causes an increase in the transition length, because of the field gradient decrease, which results in an output decrease. The decrease in head efficiency due to the increase in the CoNiFe layer thickness is negligible if the latter is less than 20% of that of the upper pole. NiFe/CoNiFe laminated heads are deemed promising for high linear density recording.
{"title":"Read-Write Characteristics of an NiFe/CoNiFe Laminated Thin-Film Head","authors":"K. Nakamoto;H. Fukui;T. Iwakura;T. Ohtsu","doi":"10.1109/TJMJ.1994.4565925","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565925","url":null,"abstract":"The read-write characteristics of thin-film heads with a NiFe/CoNiFe laminated upper pole were studied. Compared with NiFe heads, NiFe/CoNiFe laminated heads are better able to suppress loss of output and increases in disk noise, and provide better overwrite characteristics. Comparison of experimental and calculated results indicate that pole saturation causes an increase in the transition length, because of the field gradient decrease, which results in an output decrease. The decrease in head efficiency due to the increase in the CoNiFe layer thickness is negligible if the latter is less than 20% of that of the upper pole. NiFe/CoNiFe laminated heads are deemed promising for high linear density recording.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"60-65"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565925","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565919
M. Sasaki;H. Sugishita;I. Hamanaka;Y. Sasaki;K. Sueoka;T. Iwata;H. Adachi;K. Hayakawa;K. Mukasa
We developed a Mott analyzer of the spherical accelerator type, to measure the spin polarization of electrons extracted from a ferro-magnetic tip or a GaAs sample. This analyzer was designed for a low-acceleration voltage (40 kV). Inelastic scattered electrons are retarded by spherical electrodes. This paper reports on the spin polarization of electrons extracted from negative-electron affinity (NEA) GaAs. This type of Mott analyzer was found to have a few problems which require resolution.
{"title":"Analysis of a Spin-Polarized Electron Beam Using the Mott Spin Analyzer I","authors":"M. Sasaki;H. Sugishita;I. Hamanaka;Y. Sasaki;K. Sueoka;T. Iwata;H. Adachi;K. Hayakawa;K. Mukasa","doi":"10.1109/TJMJ.1994.4565919","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565919","url":null,"abstract":"We developed a Mott analyzer of the spherical accelerator type, to measure the spin polarization of electrons extracted from a ferro-magnetic tip or a GaAs sample. This analyzer was designed for a low-acceleration voltage (40 kV). Inelastic scattered electrons are retarded by spherical electrodes. This paper reports on the spin polarization of electrons extracted from negative-electron affinity (NEA) GaAs. This type of Mott analyzer was found to have a few problems which require resolution.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"21-26"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565919","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565928
S. Furukawa;S. Ohnuma;F. Matsumoto;H. Fujimori;T. Masumoto
Fe-M-(O,F) (M=Si, Mg, Y, Zr, Ca, Al) films were prepared by co-sputtering of Fe and ceramic targets. These films have a network-like structure consisting of fine metallic grains of diameter 50 to 100 Å and ceramic-like boundaries. Those films that consist of bec Fe grains have soft magnetic properties and low magnetostriction in the as-deposited state. Their permeability has good frequency response, which seems to be attributable to the reduction of eddy current losses by the highly resistive boundaries.
{"title":"Soft Magnetic Properties of Nanocrystalline Fe-Ceramic Films","authors":"S. Furukawa;S. Ohnuma;F. Matsumoto;H. Fujimori;T. Masumoto","doi":"10.1109/TJMJ.1994.4565928","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565928","url":null,"abstract":"Fe-M-(O,F) (M=Si, Mg, Y, Zr, Ca, Al) films were prepared by co-sputtering of Fe and ceramic targets. These films have a network-like structure consisting of fine metallic grains of diameter 50 to 100 Å and ceramic-like boundaries. Those films that consist of bec Fe grains have soft magnetic properties and low magnetostriction in the as-deposited state. Their permeability has good frequency response, which seems to be attributable to the reduction of eddy current losses by the highly resistive boundaries.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"80-87"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565928","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565934
O. Shinoura;A. Kamijima;Y. Narumiya
The soft magnetic properties of electrodeposited CoNiFe films were studied. Films composed of 30 to 50 wt% Co, 23 to 35 wt% Ni and 25 to 35 wt% Fe alloy with a high saturation flux density of more than 1.5 T exhibit low coercivities under 0.2 Oe. Film composed of 40 Co-30 Ni-30 Fe alloy, consisting primarily of an fcc phase with some bec phase material and created by annealing at 300°C, has excellent soft magnetic properties (H c =0.06 Oe, μ=3200, B s =1.8 T). This bcc phase makes an appearance during the first stage of crystallization at 287°C. The structure is thermally unstable, and is due to a special feature of electrodeposition. During the annealing, H 2 O, H 2 and CO 2 were released from the film, but the patterns of generation of these gases bear little relation to the DSC pattern.
{"title":"Soft Magnetic Properties of Electrodeposited CoNiFe Films","authors":"O. Shinoura;A. Kamijima;Y. Narumiya","doi":"10.1109/TJMJ.1994.4565934","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565934","url":null,"abstract":"The soft magnetic properties of electrodeposited CoNiFe films were studied. Films composed of 30 to 50 wt% Co, 23 to 35 wt% Ni and 25 to 35 wt% Fe alloy with a high saturation flux density of more than 1.5 T exhibit low coercivities under 0.2 Oe. Film composed of 40 Co-30 Ni-30 Fe alloy, consisting primarily of an fcc phase with some bec phase material and created by annealing at 300°C, has excellent soft magnetic properties (H\u0000<sub>c</sub>\u0000=0.06 Oe, μ=3200, B\u0000<inf>s</inf>\u0000=1.8 T). This bcc phase makes an appearance during the first stage of crystallization at 287°C. The structure is thermally unstable, and is due to a special feature of electrodeposition. During the annealing, H\u0000<sub>2</sub>\u0000O, H\u0000<sub>2</sub>\u0000 and CO\u0000<sub>2</sub>\u0000 were released from the film, but the patterns of generation of these gases bear little relation to the DSC pattern.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"118-123"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565934","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67893974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565935
M. Nakada;O. Okada
Repeated write and erase characteristics of quadrilayer MnBi magnetooptic disks were measured. The carrier level decreased with the number of write cycles. We found that this degradation was caused by decomposition of the MnBi low-temperature phase and by the change from the low-temperature phase to the high-temperature phase in the writing process. The rates of decomposition and phase change decreased at higher linear velocities and lower write powers. The reliability of the MnBi write cycle can be improved by optimization of the disk's thermal structure and recording conditions.
{"title":"Characteristics of Repeated Writing on MnBi Magneto-Optical Disks","authors":"M. Nakada;O. Okada","doi":"10.1109/TJMJ.1994.4565935","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565935","url":null,"abstract":"Repeated write and erase characteristics of quadrilayer MnBi magnetooptic disks were measured. The carrier level decreased with the number of write cycles. We found that this degradation was caused by decomposition of the MnBi low-temperature phase and by the change from the low-temperature phase to the high-temperature phase in the writing process. The rates of decomposition and phase change decreased at higher linear velocities and lower write powers. The reliability of the MnBi write cycle can be improved by optimization of the disk's thermal structure and recording conditions.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"124-131"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565935","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67893975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-01DOI: 10.1109/TJMJ.1994.4565939
S. Kurosawa;T. Mitu;A. Kondo
In an investigation of tape/slurry texturing for an NiP/Al alloy substrate, it was found that disks textured with alumina slurry showed better gliding performance than those textured with diamond slurry. A carbon protective layer sputtered using argon gas or argon/methane gas also improved the tribological properties of the disks, resulting in enhanced durability. Disks textured with alumina slurry and sputtered using argon/methane gas, with a carbon protective layer in place, performed well in both a gliding test at a flying height of 0.05 μm, and in CSS cycle tests with a thin-film head.
{"title":"Head Flying Characteristics and Durability of a Magnetic Disk Using Tape/Slurry Texturing","authors":"S. Kurosawa;T. Mitu;A. Kondo","doi":"10.1109/TJMJ.1994.4565939","DOIUrl":"https://doi.org/10.1109/TJMJ.1994.4565939","url":null,"abstract":"In an investigation of tape/slurry texturing for an NiP/Al alloy substrate, it was found that disks textured with alumina slurry showed better gliding performance than those textured with diamond slurry. A carbon protective layer sputtered using argon gas or argon/methane gas also improved the tribological properties of the disks, resulting in enhanced durability. Disks textured with alumina slurry and sputtered using argon/methane gas, with a carbon protective layer in place, performed well in both a gliding test at a flying height of 0.05 μm, and in CSS cycle tests with a thin-film head.","PeriodicalId":100647,"journal":{"name":"IEEE Translation Journal on Magnetics in Japan","volume":"9 5","pages":"150-157"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/TJMJ.1994.4565939","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67892836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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