JPS57152555A - Discoid magnetic recording medium - Google Patents

Discoid magnetic recording medium

Info

Publication number
JPS57152555A
JPS57152555A JP3913881A JP3913881A JPS57152555A JP S57152555 A JPS57152555 A JP S57152555A JP 3913881 A JP3913881 A JP 3913881A JP 3913881 A JP3913881 A JP 3913881A JP S57152555 A JPS57152555 A JP S57152555A
Authority
JP
Japan
Prior art keywords
tbfe
recording
density
outer circumference
rate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP3913881A
Other languages
Japanese (ja)
Inventor
Masaaki Nomura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP3913881A priority Critical patent/JPS57152555A/en
Publication of JPS57152555A publication Critical patent/JPS57152555A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/74—Record carriers characterised by the form, e.g. sheet shaped to wrap around a drum
    • G11B5/82—Disk carriers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
    • G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
    • G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing

Abstract

PURPOSE:To make signal pulse width and amplitude constant and also to prevent the contrast of recording bits from decreasing even at an outer circumference, by continuously varying the composition rate of magnetic materials. CONSTITUTION:A discoid magnetic recording mdium which performs magnetic recordingly by using as a recording carier a thin film of an amorphous magnetic material made of a rare earth metal and an iron group metal has the composition rate of both said metals varied continuously in the radius direction of the recording medium to increase the content rate of the iron group metal gradually on its outer circumference side. When TbFe is used as the amorphous magnetic material, the thin film is formed uniformly conventionally to obtain 24at% TbFe density, but the TbFe composition ratio on the disk is varied continuously from the internal diameter to the external diameter to make the Curie point of the inner circumference higher than that of the outer circumference. To be concrete, 26at% TbFe density is obtained at the internal diameter part and 20at% TbFe density is obtained at the external diameter part; and the composition rate is varied linearly between the both.
JP3913881A 1981-03-18 1981-03-18 Discoid magnetic recording medium Pending JPS57152555A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3913881A JPS57152555A (en) 1981-03-18 1981-03-18 Discoid magnetic recording medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3913881A JPS57152555A (en) 1981-03-18 1981-03-18 Discoid magnetic recording medium

Publications (1)

Publication Number Publication Date
JPS57152555A true JPS57152555A (en) 1982-09-20

Family

ID=12544742

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3913881A Pending JPS57152555A (en) 1981-03-18 1981-03-18 Discoid magnetic recording medium

Country Status (1)

Country Link
JP (1) JPS57152555A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6450255A (en) * 1987-08-20 1989-02-27 Fujitsu Ltd Magneto-optical disk
EP0446784A2 (en) * 1990-03-14 1991-09-18 BASF Aktiengesellschaft Magnetooptical data disk
US5486395A (en) * 1991-12-05 1996-01-23 Sharp Kabushiki Kaisha Magneto-optical disk

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6450255A (en) * 1987-08-20 1989-02-27 Fujitsu Ltd Magneto-optical disk
EP0446784A2 (en) * 1990-03-14 1991-09-18 BASF Aktiengesellschaft Magnetooptical data disk
US5486395A (en) * 1991-12-05 1996-01-23 Sharp Kabushiki Kaisha Magneto-optical disk

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