KR100546567B1 - Magneto-optical recording media and manufacturing method thereof - Google Patents
Magneto-optical recording media and manufacturing method thereof Download PDFInfo
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- KR100546567B1 KR100546567B1 KR1019980036582A KR19980036582A KR100546567B1 KR 100546567 B1 KR100546567 B1 KR 100546567B1 KR 1019980036582 A KR1019980036582 A KR 1019980036582A KR 19980036582 A KR19980036582 A KR 19980036582A KR 100546567 B1 KR100546567 B1 KR 100546567B1
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- 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
- G11B11/10582—Record carriers characterised by the selection of the material or by the structure or form
- G11B11/10584—Record carriers characterised by the selection of the material or by the structure or form characterised by the form, e.g. comprising mechanical protection elements
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- 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
- G11B11/10582—Record carriers characterised by the selection of the material or by the structure or form
- G11B11/10586—Record carriers characterised by the selection of the material or by the structure or form characterised by the selection of the material
Abstract
층 구조가 단순화된 광자기 기록매체 및 그 제조방법에 관한 것으로, 재생층 형성시, 하나의 GdFeCo 타겟을 이용한 스퍼터링 방법으로 압력 조건을 변화시키면서 재생층의 조성이 기판에서 기록층 방향으로 Gd28(FeCo)72 ∼ Gd35(FeCo)65 인 그레디언트를 갖도록 형성함으로써, 재생 특성(CNR) 안정하고 공정이 단순화되어 시간 및 비용을 절감할 수 있다.Relates to a layer of a magneto-optical recording medium and a method of manufacturing the simplified structure, upon formation of the reproducing layer, by varying the pressure conditions by a sputtering method using a single GdFeCo target from the composition of the substrate of the reproduction layer as a recording layer direction Gd 28 ( By forming to have a gradient of FeCo) 72 to Gd 35 (FeCo) 65 , the regeneration characteristics (CNR) is stable and the process can be simplified to save time and cost.
Description
본 발명은 광자기 기록매체에 관한 것으로, 층 구조가 단순화된 광자기 기록매체 및 그 제조방법에 관한 것이다.The present invention relates to a magneto-optical recording medium, and more particularly, to a magneto-optical recording medium having a simplified layer structure and a manufacturing method thereof.
최근들어 고밀도 정보기록/재생에 대한 요구가 커지면서 레이저 광을 이용한 고밀도 기록이 큰 관심을 끌고 있다.Recently, as the demand for high-density information recording / reproducing increases, high-density recording using laser light has attracted great attention.
그 중, 광자기 디스크는 정보의 반복기록과 소거가 가능하고 고밀도화를 용이하게 구현할 수 있어 금후 발전이 상당히 기대되는 기록매체이므로 최근 이에 대한 연구가 활발히 진행되고 있다.Among them, the magneto-optical disk is a recording medium that can be repeatedly recorded and erased of information and can be easily implemented with high density. Therefore, research on this has been actively conducted in recent years.
광자기 디스크는 수직자화 박막에 레이저 광과 자기장을 이용하여 자구(magnetic domain)를 형성하여 정보를 기록하고, 자기광학효과를 이용하여 정보를 재생하는 것으로 기록층 재료로는 희토류-천이금속 합금계(RE-TM)를 많이 사용하고 있다.Magneto-optical disk records information by forming magnetic domain using laser light and magnetic field on vertical magnetized thin film and reproduces information by using magneto-optical effect. Rare earth-transition metal alloy system (RE-TM) is used a lot.
여기서, 천이금속은 강자성 원소인 Fe, Co 등이며, 희토류 원소는 Tb, Dy, Gd, Sm, Ho 등이다.Here, the transition metals are Fe, Co, etc., which are ferromagnetic elements, and the rare earth elements are Tb, Dy, Gd, Sm, Ho, and the like.
이러한 광자기 디스크에서 가장 큰 목표중의 하나는 단위 면적안에 보다 많은 정보를 기록하고 오류없이 재생하는 것이다.One of the biggest goals of such magneto-optical discs is to record more information in a unit area and reproduce it without errors.
그러므로 기록밀도를 높이기 위해서는 자구의 크기를 작게할 필요가 있다.Therefore, in order to increase the recording density, it is necessary to reduce the size of the magnetic domain.
그러나, 자구를 작게하기 위해서는 레이저 광의 파장을 더 짧게해야 하고, 자구를 작게 형성하여 기록한 후에도 그 자구를 재생하는 과정에서 신호의 크기가 작아 어려움이 많았다.However, in order to make the magnetic domain smaller, the wavelength of the laser light must be shorter, and even after the formation and recording of the magnetic domain is small, the magnitude of the signal is difficult in the process of reproducing the magnetic domain.
그 이유는 재생빔(스팟)의 직경보다 작은 자구를 재생하는 과정에서 인접한 자구로부터 신호가 유입되어 노이즈가 커져 신호와 잡음의 비(carrier-to-noise ratio)가 상대적으로 감소되는 문제가 생겨 재생 오류를 일으키는 문제가 발생하기 때문이다.The reason for this is that in the process of regenerating magnetic domains smaller than the diameter of the reproduction beam (spot), the signal is introduced from adjacent magnetic domains, and the noise increases, so that the signal-to-noise ratio decreases relatively. This is because a problem occurs that causes an error.
그러므로 이러한 문제들을 해결하기 위해서는 특별한 방법들이 필요하였다.Therefore, special methods were needed to solve these problems.
그 중 첫 번째 방법으로는 먼저 읽을 때, 레이저 빔의 온도가 높은 재생층의 가운데 부분에서만 창(window)을 열어 기록층의 신호를 복제하는 메카니즘(mechanism)을 이용하는 방법이었다.In the first method, a method of using a mechanism of replicating a signal of the recording layer by opening a window only in the center of the reproduction layer having a high temperature of the laser beam is read.
이 방법에서 재생층의 자화방향은 상온에서 수평이다.In this method, the magnetization direction of the regeneration layer is horizontal at room temperature.
두 번째 방법으로는 더욱더 기록 밀도를 높이기 위하여 기록 마크를 작게 했을 때, 읽어내려는 신호의 크기가 작은 문제를 해결하기 위하여 기록층의 기록된 마크를 재생층에서 확대시켜서 재생 신호를 크게하는 방법이었다.The second method is to enlarge the playback signal by enlarging the recorded mark in the recording layer in the reproduction layer in order to solve the problem that the size of the signal to be read is small when the recording mark is made smaller to increase the recording density.
이와 같은 방법에서는 재생시 해상도를 향상시키기 위하여 기록층과 재생층 사이에 중간층을 삽입하여 사용하였다.In this method, an intermediate layer is inserted between the recording layer and the reproduction layer in order to improve the resolution during reproduction.
도 1은 종래 기술에 따른 광자기 디스크를 보여주는 도면으로서, 도 1에 도시된 바와 같이, 기판/제 1 유전체층/재생층/중간층/기록층/제 2 유전체층으로 이루어지는데, 재생층과 중간층이 수평 자기 이방성을 갖는 이중 인-플레인(double in-plane)층을 이용한 것이다.1 is a view showing a magneto-optical disk according to the prior art, and as shown in FIG. 1, comprising a substrate / first dielectric layer / reproduction layer / intermediate layer / recording layer / second dielectric layer, wherein the reproduction layer and the intermediate layer are horizontal. It uses a double in-plane layer with magnetic anisotropy.
여기서, 중간층은 Gd33(FeCo)67 정도의 조성을 가지고, 재생층은 Gd30(FeCo)70 정도의 조성을 가지는데, 수평 자기에서 수직 자기로의 전이온도가 다른 특성을 이용한다.Here, the intermediate layer has a composition of about Gd 33 (FeCo) 67 , and the regeneration layer has a composition of about Gd 30 (FeCo) 70 , and uses a characteristic in which the transition temperature from the horizontal magnet to the vertical magnet is different.
특히, 중간층의 Gd33(FeCo)67 은 재생층의 Gd30(FeCo)70 에 비해 전이온도가 높기 때문에 도 1에 도시된 바와 같이 기록된 작은 비트의 분해능(resolution)이 향상된다.In particular, since the transition temperature of Gd 33 (FeCo) 67 of the intermediate layer is higher than that of Gd 30 (FeCo) 70 of the reproduction layer, the resolution of the recorded small bits is improved as shown in FIG.
재생시, 낮은 파워의 레이저 빔이 조사되면 전이온도가 낮은 재생층에 기록층의 자구가 전사되는데, 이때의 자구들은 원하는 자구 이외에 인접한 다른 자구들까지 전사되어 신호 특성이 좋지 않지만 높은 파워의 레이저 빔이 조사되면 전이온도가 높은 중간층에서 원하는 기록층의 자구만 전사되고 그 전사된 자구를 재생층에서 확대재생함으로써, 신호의 품질을 향상시켜 해상도를 높일 수 있다.During reproduction, when the low power laser beam is irradiated, the magnetic domain of the recording layer is transferred to the reproduction layer having a low transition temperature. At this time, the magnetic domains are transferred to other adjacent magnetic domains in addition to the desired magnetic domain, so that the signal characteristics are poor but the high power laser beam is transmitted. When irradiated, only the magnetic domain of the desired recording layer is transferred in the intermediate layer having a high transition temperature, and the transferred magnetic domain is enlarged and reproduced in the reproduction layer, thereby improving the signal quality and increasing the resolution.
종래 기술에 따른 광자기 기록 매체에 있어서는 다음과 같은 문제점이 있었다.In the magneto-optical recording medium according to the prior art, there are the following problems.
이중 인-플레인(double in-plane)층을 이용하면 단일 인-플레인(single in-plane)층을 사용한 것보다 신호 특성은 좋아지지만 제조공정시 재생층과 중간층은 각각의 스퍼터링 타겟을 제작해야 하므로 공정이 복잡하고 불필요한 시간 및 비용이 발생한다.Using a double in-plane layer provides better signal characteristics than using a single in-plane layer, but the regeneration layer and intermediate layer have to produce their respective sputtering targets during the manufacturing process. The process is complex and incurs unnecessary time and costs.
본 발명은 이와 같은 문제들을 해결하기 위한 것으로, 재생층의 조성을 조절하여 신호 특성이 좋으면서도 제조공정이 간단한 광자기 기록매체 및 그 제조방법을 제공하는 데 그 목적이 있다.SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and an object thereof is to provide a magneto-optical recording medium having a good signal characteristic and a simple manufacturing process by adjusting the composition of a reproduction layer and a method of manufacturing the same.
본 발명에 따른 광자기 기록매체의 주요 특징은 재생층이 GdFeCo로 이루어지고, GdFeCo의 조성비가 두께 방향으로 그레디언트(gradient)를 갖는데 있다.The main feature of the magneto-optical recording medium according to the present invention is that the reproduction layer is made of GdFeCo, and the composition ratio of GdFeCo has a gradient in the thickness direction.
본 발명의 다른 특징은 재생층의 조성이 기판에서 기록층 방향으로 Gd28(FeCo)72 ∼ Gd35(FeCo)65 인 그레디언트를 갖는데 있다.Another feature of the present invention is that the composition of the reproduction layer has a gradient of Gd 28 (FeCo) 72 to Gd 35 (FeCo) 65 in the direction of the recording layer in the substrate.
본 발명에 따른 광자기 기록 매체의 제조방법은 기판 위에 제 1 유전체층을 형성하는 단계와, 제 1 유전체층 위에 하나의 GdFeCo 타겟을 이용한 스퍼터링 방법으로 압력 조건을 변화시키면서 조성비가 그레디언트를 갖도록 재생층을 형성하는 단계와, 재생층 위에 기록층, 제 2 유전체층을 순차적으로 형성하는 단계로 이루어지는데 있다.The method of manufacturing a magneto-optical recording medium according to the present invention comprises the steps of forming a first dielectric layer on a substrate, and forming a reproduction layer such that a composition ratio has a gradient while changing pressure conditions by a sputtering method using one GdFeCo target on the first dielectric layer. And sequentially forming a recording layer and a second dielectric layer on the reproduction layer.
상기와 같은 특징을 갖는 본 발명에 따른 광자기 기록매체 및 그 제조방법을 첨부된 도면을 참조하여 설명하면 다음과 같다.Referring to the accompanying drawings, a magneto-optical recording medium and a method of manufacturing the same according to the present invention having the above characteristics are as follows.
먼저, 본 발명의 개념은 상온에서 인-플레인 자기 이방성을 갖는 재생층을 제작할 때, 두께 방향으로 조성을 변조하여 작게 기록된 비트(bit)를 자기 초해상 또는 외부 자장을 이용하여 확대 재생함으로써, 기존의 중간층 없이도 안정된 재생 특성을 보여주고 공정을 단순화하는데 있다.First, the concept of the present invention is to produce a reproduction layer having in-plane magnetic anisotropy at room temperature, by modulating the composition in the thickness direction to enlarge and reproduce a small recorded bit using a magnetic super-resolution or an external magnetic field, It shows stable regeneration characteristics and simplifies the process without the intermediate layer of.
도 2는 본 발명에 따른 광자기 기록매체를 보여주는 도면으로서, 도 2에 도시된 바와 같이, 광자기 기록매체는 기판(11)위에 순차적으로 적층되는 제 1 유전체층(12), 조성이 변조된 재생층(13), 기록층(14), 제 2 유전체층(15)으로 구성된다.FIG. 2 is a view showing a magneto-optical recording medium according to the present invention. As shown in FIG. 2, the magneto-optical recording medium is a first dielectric layer 12 sequentially stacked on the substrate 11, and the composition is modulated and reproduced. The layer 13, the recording layer 14, and the second dielectric layer 15 are constituted.
여기서, 조성 변조 재생층(13)과 기록층(14) 사이에 또 다른 유전체층을 둘 수도 있다.Here, another dielectric layer may be provided between the composition modulation reproduction layer 13 and the recording layer 14.
또한, 재생층(13)의 재료는 기존과 같이 GdFeCo로 이루어지는데, 종래 기술인 중간층과 같은 역할을 수행할 수 있도록 재생층(13)의 조성을 기판(11)에서 기록층(14) 방향으로 Gd28(FeCo)72 ∼ Gd35(FeCo)65 인 그레디언트(gradient)를 갖도록 변조시킨다.In addition, the material of the reproduction layer 13 is made of GdFeCo as before, and the composition of the reproduction layer 13 is changed from the substrate 11 to the recording layer 14 in the direction of Gd 28 so as to perform the same role as the conventional intermediate layer. It modulates to have a gradient of (FeCo) 72 to Gd 35 (FeCo) 65 .
이 재생층(13)에서 기록층(14)에 가까운 부분이 기록층(14)에서 먼 부분보다 수평, 수직 전이온도가 더 높아 기존의 중간층과 같은 역할을 수행하게 된다.The portion closer to the recording layer 14 in the reproduction layer 13 has a higher horizontal and vertical transition temperature than the portion farther from the recording layer 14 to play the same role as the existing intermediate layer.
그 이유는 수평에서 수직 방향으로 자기 이방성이 변화하는 전이온도가 Gd 양에 비례하기 때문이다.This is because the transition temperature at which magnetic anisotropy changes from horizontal to vertical is proportional to the amount of Gd.
즉, 도 2에 도시된 바와 같이 상온에서 재생층(13)은 수평 자기 이방성을 갖지만 재생을 위한 레이저 빔이 조사되면 재생층(13)은 특정온도 부분에서 수직 자기 이방성을 갖는다.That is, as shown in FIG. 2, the reproduction layer 13 has horizontal magnetic anisotropy at room temperature, but when the laser beam for reproduction is irradiated, the reproduction layer 13 has vertical magnetic anisotropy at a specific temperature portion.
이때, 낮은 파워의 레이저 빔이 조사되면 전이온도가 낮은 기록층(14)에서 먼 부분의 재생층에 기록층의 자구가 전사되는데, 이때의 자구들은 원하는 자구 이외에 인접한 다른 자구들까지 전사되어 신호 특성이 좋지 않지만 높은 파워의 레이저 빔이 조사되면 전이온도가 높은 기록층(14)에 가까운 부분에 원하는 기록층의 자구가 전사되고 그 전사된 자구를 기록층(14)에서 먼 부분의 재생층에서 확대재생할 수 있어 신호 특성이 좋다.At this time, when the laser beam of low power is irradiated, the magnetic domain of the recording layer is transferred to the reproduction layer far away from the recording layer 14 having a low transition temperature, and the magnetic domains are transferred to other adjacent magnetic domains in addition to the desired magnetic domain. When this poor but high power laser beam is irradiated, the magnetic domain of the desired recording layer is transferred to a portion close to the recording layer 14 having a high transition temperature, and the transferred magnetic domain is enlarged in the reproduction layer away from the recording layer 14. Can reproduce and have good signal characteristics.
이 경우 종래 구조에 비하여 안정된 재생 특성(CNR)을 보여줄 뿐만 아니라, 하나의 스퍼터링 타겟(sputtering target)을 이용하여 하나의 공정으로 재생층의 조성 변조를 시킬 수 있어 공정이 단순화되는 잇점이 있다.In this case, not only shows a stable reproducing characteristic (CNR) compared to the conventional structure, but also one of the sputtering target (sputtering target) can be modulated composition of the regeneration layer in one process has the advantage of simplifying the process.
이와 같은 본 발명의 제조공정을 설명하면 다음과 같다.Referring to the manufacturing process of the present invention as follows.
재생층을 제외한 다른 층들은 기존과 동일한 방법으로 제작되므로 상세한 설명은 생략하기로 한다.Since the other layers except for the reproduction layer are manufactured in the same manner as before, the detailed description thereof will be omitted.
도 2에 도시된 바와 같이, 기판(11) 위에 제 1 유전체층(12)을 형성하고, 제 1 유전체층(12) 위에 조성 변조 재생층(13)을 형성한다.As shown in FIG. 2, the first dielectric layer 12 is formed on the substrate 11, and the composition modulated reproduction layer 13 is formed on the first dielectric layer 12.
여기서, 재생층(13)은 스퍼터링 방법으로 형성하는데, 타겟은 GdFeCo인 합금 타겟 하나만을 이용한다.Here, the regeneration layer 13 is formed by the sputtering method, using only one alloy target, which is GdFeCo.
그리고, 조성 변조를 위해 조건중에서 압력 조건을 변화시킨다.Then, the pressure condition is changed among the conditions for the composition modulation.
압력 조건을 변화시키는 이유는 고압이 됨에 따라 타겟의 Fe, Co와 같은 상대적으로 가벼운 원자들이 스캐터링(scattering)되어 Gd-rich 조성으로 되기 때문이다.The reason for changing the pressure condition is that as the high pressure increases, relatively light atoms such as Fe and Co of the target are scattered into the Gd-rich composition.
그러므로 챔버내의 압력 조건을 점차적으로 높여 재생층(13)이 아래에서 위로 갈수록 Gd-rich인 조성을 갖도록 변조시킨다.Therefore, the pressure conditions in the chamber are gradually raised to modulate the regeneration layer 13 to have a composition that is Gd-rich from bottom to top.
예를 들면, Gd31.5(FeCo)68.5 조성을 갖는 타겟을 사용하는 경우, Ar압력 약 1.2 ∼ 4.8 mTorr에서 Gd30(FeCo)70 ∼ Gd33(FeCo)67 인 조성 변조가 가능하였다.For example, when a target having a composition of Gd 31.5 (FeCo) 68.5 was used, a composition modulation of Gd 30 (FeCo) 70 to Gd 33 (FeCo) 67 at an Ar pressure of about 1.2 to 4.8 mTorr was possible.
이어, 조성 변조 재생층(13) 위에 기록층(14), 제 2 유전체층(15)을 순차적으로 형성하여 광자기 기록 매체를 제작한다.Subsequently, the recording layer 14 and the second dielectric layer 15 are sequentially formed on the composition modulating reproduction layer 13 to produce a magneto-optical recording medium.
이와 같이 조성 변조 재생층을 자기 초해상(MSR), 자구확대재생(MAMMOS) 등과 같은 광자기 기록 매체들에 이용하면 간단한 제작공정으로 재생 특성(CNR)을 향상시킬 수 있다.As such, when the composition modulated reproduction layer is used for magneto-optical recording media such as magnetic super resolution (MSR), magnetic domain enlarged reproduction (MAMMOS), etc., the reproduction characteristics (CNR) can be improved by a simple manufacturing process.
본 발명에 따른 광자기 기록매체에 있어서는 다음과 같은 효과가 있다.The magneto-optical recording medium according to the present invention has the following effects.
조성이 변조된 재생층을 이용함으로써, 안정된 재생 특성(CNR)을 보여줄 뿐만 아니라, 하나의 스퍼터링 타겟(sputtering target)을 이용하므로 공정이 단순화되어 시간 및 비용을 절감할 수 있다.The use of a modulated regenerated layer not only shows stable regeneration characteristics (CNR), but also uses a single sputtering target, which simplifies the process and saves time and money.
도 1은 종래 기술에 따른 광자기 기록매체를 보여주는 도면1 is a view showing a magneto-optical recording medium according to the prior art.
도 2은 본 발명에 따른 광자기 기록매체를 보여주는 도면2 shows a magneto-optical recording medium according to the present invention.
도면의 주요부분에 대한 부호의 설명Explanation of symbols for main parts of the drawings
11 : 기판 12 : 제 1 유전체층11 substrate 12 first dielectric layer
13 : 재생층 14 : 기록층13: playback layer 14: recording layer
15 : 제 2 유전체층15: second dielectric layer
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06333285A (en) * | 1993-03-22 | 1994-12-02 | Tosoh Corp | Magneto-optical recording medium and manufacturing method thereof |
| JPH07254179A (en) * | 1994-03-15 | 1995-10-03 | Nikon Corp | Magneto-optical recording medium and its production |
| JPH1021598A (en) * | 1996-07-02 | 1998-01-23 | Fujitsu Ltd | Magneto-optical recording medium and recording / reproducing apparatus therefor |
| JPH1027392A (en) * | 1996-07-10 | 1998-01-27 | Fujitsu Ltd | Magneto-optical recording medium |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06333285A (en) * | 1993-03-22 | 1994-12-02 | Tosoh Corp | Magneto-optical recording medium and manufacturing method thereof |
| JPH07254179A (en) * | 1994-03-15 | 1995-10-03 | Nikon Corp | Magneto-optical recording medium and its production |
| JPH1021598A (en) * | 1996-07-02 | 1998-01-23 | Fujitsu Ltd | Magneto-optical recording medium and recording / reproducing apparatus therefor |
| JPH1027392A (en) * | 1996-07-10 | 1998-01-27 | Fujitsu Ltd | Magneto-optical recording medium |
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