KR100209584B1 - Magneto-optical disk - Google Patents
Magneto-optical disk Download PDFInfo
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- KR100209584B1 KR100209584B1 KR1019950001797A KR19950001797A KR100209584B1 KR 100209584 B1 KR100209584 B1 KR 100209584B1 KR 1019950001797 A KR1019950001797 A KR 1019950001797A KR 19950001797 A KR19950001797 A KR 19950001797A KR 100209584 B1 KR100209584 B1 KR 100209584B1
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- optical disk
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
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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
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2403—Layers; Shape, structure or physical properties thereof
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
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Abstract
본 발명은 기록재생특성을 향상한 광자기 디스크에 관한 것으로서, 좀 더 상세하게는 기판상에 제1유전체막, 희토류-천이원소계 기록막, 제2유전체막, 반사막 및 보호막이 순차적으로 적층된 광자기 디스크에 있어서, 상기 기록막과 제2유전체막의 사이에 산화막이 형성되고, 상기 산화막의 조성이 (희토류-천이원소계)100-x(O)x으로 표시되는 광자기 디스크에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk having improved recording and reproducing characteristics, and more particularly, a first dielectric film, a rare earth-transition element recording film, a second dielectric film, a reflection film, and a protective film sequentially stacked on a substrate. A magneto-optical disc, wherein an oxide film is formed between the recording film and the second dielectric film, and the composition of the oxide film is expressed as (rare earth-transition element system) 100-x (O) x .
Description
제1도는 종래의 광자기 디스크의 적층구조를 개략적으로 도시한 단면도.1 is a cross-sectional view schematically showing a laminated structure of a conventional magneto-optical disk.
제2도는 본 발명에 따른 광자기 디스크의 적층구조를 개략적으로 도시한 단면도.2 is a cross-sectional view schematically showing the laminated structure of the magneto-optical disk according to the present invention.
제3도는 종래의 광자기 디스크의 외부자계에 따른 기록재생특성을 나타낸 그래프.3 is a graph showing recording and reproduction characteristics according to an external magnetic field of a conventional magneto-optical disk.
제4도는 본 발명의 광자기 디스크의 외부자계에 따른 기록재생특성을 나타낸 그래프.4 is a graph showing recording and reproduction characteristics according to the external magnetic field of the magneto-optical disk of the present invention.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
1,11 : 기판 2, 12 : 제1유전체막1,11 substrate 2,12 first dielectric film
3, 13 : 기록막 4, 14 : 제2유전체막3, 13: recording film 4, 14: second dielectric film
5, 15 : 반사막 6, 16 : 보호막5, 15: reflective film 6, 16: protective film
17 : 산화막17: oxide film
본 발명은 기록재생특성을 향상시킨 광자기 디스크에 관한 것으로서, 좀 더 상세하게는 자기적인 직접기록방법을 이용하는 종래의 4층구조 광자기 디스크에 산화막을 삽입시키므로써 기록시에 외부자계 감도를 향상시킨 5층구조의 광자기 디스크에 관한 것이다.The present invention relates to a magneto-optical disk with improved recording and reproducing characteristics. More particularly, the external magnetic field sensitivity is improved during recording by inserting an oxide film into a conventional four-layered magneto-optical disk using a magnetic direct recording method. It relates to a five-layered magneto-optical disk.
현재 상용화되어 있는 광자기 디스크들은 제1도에 도시된 바와같이 대부분이 4층구조의 기록층을 채용하고 있다. 이와같은 종래의 광자기 디스크의 층구조는 기판상에 제1유전체막/기록막/제2유전체막/반사막/보호막으로 이루어지며, 제1세대 광자기 디스크 및 미니 디스크(mini-disk, MD) 녹음가능형 디스크등에 사용되고 있으며, 향후 디지탈 비디오 디스크 및 레코더용 기록가능형 디스크로도 사용될 전망이다.Most commercially available magneto-optical disks employ a four-layer recording layer, as shown in FIG. The layer structure of such a conventional magneto-optical disk is composed of a first dielectric film / recording film / second dielectric film / reflection film / protective film on the substrate, the first generation magneto-optical disk and mini-disk (mini-disk, MD) It is used in recordable discs and is expected to be used as recordable discs for digital video discs and recorders in the future.
제1세대로 불리우는 광자기 디스크 및 드라이브는 5.25와 3.5의 두종류가 있으며, 기억용량은 각각 650MB/양면과 128MB/단면이며, 디스크의 기록층구조는 종래의 4층구조 기록층을 채용하였다. 또한, 제2세대로 불리우는 광자기 디스크 및 드라이브는 기록용량이 각각 1.3GB/양면과 230MB/단면이며, 이것도 역시 종래의 4층구조의 기록층을 채용하고 있다. 이들 제1세대와 제2세대 광자기 디스크에서는 직접기록이라는 방법을 채용하지 않고 있으며, 따라서 기록시에는 종래에 기록되었던 데이타를 지우기 위해 디스크를 한바퀴 더돌려야 하였다. 이에 따라 직접기록을 기본으로 채용하고 있는 자기디스크와의 속도경쟁에서 뒤질 수 밖에 없으며, 실시간 기록이 요구되는 음악용 및 영상용 기록매체로의 적용에 제약이 되어왔다. 최근, 일본의 소니(SONY), 니콘(NIKON), 엔이씨(NEC)동의 유수한 기업들이 이의 문제점을 해결하기 위해 자기적인 직접기록 방법과 광학적인 직접기록 방법등을 제안하고 있다. 자기적인 직접기록 방법은 기록시 레이저광을 높은 출력으로 계속 유지하면서 디스크의 반대편에 있는 활강자기헤드의 외부자계를 위 또는 아래방향으로 빠르게 바꿔주면 원하는 기록비트가 형성되는 원리를 이용한 것이다. 이와같은 방법을 적용하는데 있어서 기술적으로 어려운 점으로서, 첫째는 외부자계를 수MHz의 주파수로 위/아래방향으로 바꾸어 줄 수 있는 자기헤드의 개발과, 둘째는 기록막에 근접해서 비행하는 자기헤드를 제조하는 것, 그리고 마지막으로 약한 외부자계에도 손쉽게 자화방향이 바뀌는 즉, 외부자계에 대한 감도가 우수한 기록막을 제조하는 것이다.There are two types of magneto-optical disks and drives called the first generation, 5.25 and 3.5, and the storage capacities are 650MB / two sides and 128MB / single, respectively, and the recording layer structure of the disc is a conventional four-layer recording layer. In addition, the magneto-optical disc and the drive called the second generation have recording capacities of 1.3GB / both sides and 230MB / segment, respectively, and this also employs a conventional four-layer recording layer. These first generation and second generation magneto-optical discs do not employ a direct recording method. Therefore, during recording, the disc has to be rotated one more time to erase data that has previously been recorded. As a result, they have to lag behind the speed competition with magnetic disks employing direct recording as a basis, and have been restricted in their application to music and video recording media that require real-time recording. Recently, leading companies such as Sony, Nikon and NEC in Japan have proposed magnetic direct recording methods and optical direct recording methods to solve the problems. The magnetic direct recording method uses the principle that the desired recording bit is formed by rapidly changing the external magnetic field of the sliding magnetic head on the opposite side of the disk in the up or down direction while maintaining the laser light at a high output during recording. Technically difficult to apply this method, the first is the development of a magnetic head that can change the external magnetic field up and down by a frequency of several MHz, and the second is to develop a magnetic head flying close to the recording film Finally, the magnetization direction is easily changed even in the weak external magnetic field, that is, the recording film having excellent sensitivity to the external magnetic field is manufactured.
종래의 4층구조의 기록층을 채용한 광자기 디스크의 외부자계에 따른 기록재생특성(CNR)은 외부자계가 250 Oe(Oersted)일 때 포화되며, 또한 외부자계가 0 Oe일때도 30 dB가 넘는 기록재생특성(CNR)을 나타내는데, 이와 같은 외부자계감도는 직접기록방법(DOW)을 채용하지 않는 경우에도 자기헤드의 플립(flip) 주파수가 매우 낮으며, 또한 기록면과 근접해서 활주할 필요도 없기 때문에 문제가 되지 않으며, 이와 같은 조건의 자기헤드를 제조하는 것은 매우 용이하며, 플립 주파수가 낮은 만큼 소비전력 및 발열문제도 없게 된다.The recording and reproducing characteristic (CNR) according to the external magnetic field of the conventional magneto-optical disk employing the four-layer recording layer is saturated when the external magnetic field is 250 Oe (Oersted), and 30 dB even when the external magnetic field is 0 Oe. The external magnetic sensitivity is such that even when the direct recording method (DOW) is not employed, the flip frequency of the magnetic head is very low, and it is necessary to slide close to the recording surface. Since it is not a problem, it is very easy to manufacture a magnetic head under such conditions, and as the flip frequency is low, there is no power consumption and heat generation problems.
그러나, 자기적인 직접기록방법을 채용할 경우는 자기헤드의 플립주파수가 수MHz에 달해, 250 Oe의 외부자계를 인가할 수 있는 자기헤드를 제조하기가 매우 어려우며, 비록 제조는 가능하다고 하더라도 이에 필요한 소비전력이나 이때 발생하는 열을 방출시키는 문제가 있었다.However, when the magnetic direct recording method is adopted, it is very difficult to manufacture a magnetic head capable of applying an external magnetic field of 250 Oe, since the flip frequency of the magnetic head reaches several MHz. There was a problem in releasing power consumption or heat generated at this time.
종래의 4층구조에서는 유전체막 사이에 기록막이 위치되는데 상기 기록막은 상온에서 수직자화성질을 갖는 박막으로 주로 희토류(rate earth, RE) 원소와 천이금속(transition metal, TM)의 합금으로 구성된다.In a conventional four-layer structure, a recording film is positioned between dielectric films. The recording film is a thin film having perpendicular magnetization properties at room temperature, and is mainly composed of an alloy of a rare earth element and a transition metal (TM).
상기 희토류-천이금속 합금 박막은 수직이방성 에너지(perpendicular anisotropy energy)가 커서 기록막에 수직한 방향으로만 스핀(spin)이 배열하게 되며, 상온에서는 수kOe의 외부자계에도 자화방향이 바뀌지 않는다. 즉, 기록막의 보자력(coercivity)은 상온에서 5 kOe 이상인 것이 일반적이다. 기록막의 보자력은 온도가 높아질수록 줄어들어서 큐리온도(curie temperature, Tc)에 도달하면 0 Oe가 된다. 디스크상에서의 기록과정은 이와 같은 성질을 이용한 것으로, Φ1㎛정도로 집속된 레이저광을 고출력으로 기록막에 조사하면 레이저광이 조사된 부분만 온도가 올라가게 되며, 온도가 Tc에 근접해지면 약한 외부자계, 예를들어 300 Oe정도의 외부자계에도 자화방향이 반전되는 성질을 이용하는 과정인 것이다. 데이타를 지울 때(소거과정)에도 같은 원리를 이용한다. 상기에 설명한 바와 같이 종래의 기록층 구조는 기록층내에 자성을 갖는 막이 기록막 한층막에 없으므로 기록막의 위 및/또는 아래로 유전체막이 위치해서 기록막으로 부터 나오는 자속이 마치 공기중에 나오는 것과 같게 되므로 기록막의 수직자기이방성 에너지가 감소되지 않고 증가되는 문제점이 있었다.The rare earth-transition metal alloy thin film has a high perpendicular anisotropy energy so that spin is arranged only in a direction perpendicular to the recording film, and the magnetization direction does not change even at an external magnetic field of several kOe at room temperature. That is, the coercivity of the recording film is generally 5 kOe or more at room temperature. The coercive force of the recording film decreases as the temperature increases, and becomes 0 Oe when the curie temperature (Tc) is reached. The recording process on the disk uses this property. When the laser beam focused at Φ1 μm is irradiated to the recording film with high power, only the portion where the laser light is irradiated rises in temperature, and when the temperature approaches Tc, the weak external magnetic field For example, it is a process using the property that the magnetization direction is reversed even in the external magnetic field of about 300 Oe. The same principle is used to erase data (erasing). As described above, in the conventional recording layer structure, since there is no magnetic film in the recording layer, the dielectric film is positioned above and / or below the recording film so that the magnetic flux from the recording film is as if it is in the air. There was a problem in that the perpendicular magnetic anisotropy energy of the recording film was not decreased but increased.
따라서, 본 발명의 목적은 상술한 문제점을 해결하기 위하여 기록막으로부터 나오는 기록막의 자속을 제한하고 기록막의 수직자기이방성 에너지를 보존시켜서 외부자계에 대한 감도를 향상시킨 5층구조의 광자기 디스크를 제공하는데 있다.Accordingly, an object of the present invention is to provide a five-layered magneto-optical disk which improves sensitivity to external magnetic fields by limiting the magnetic flux of the recording film coming out of the recording film and preserving the perpendicular magnetic anisotropy energy of the recording film to solve the above problems. It is.
상기의 목적을 달성하기 위한 본 발명의 광자기 디스크는 데이타를 기록, 재생 및 보존할 수 있도록 기판상에 제1유전체막, 기록막, 제2유전체막, 반사막 및 보호막이 순차적으로 적층된 광자기 디스크에 있어서, 상기 기록막과 제2유전체막의 사이에 산화막을 형성시키며, 상기 산화막의 조성이 (희토류-천이원소계)100-x(O)x식으로 표시되는 것으로 구성된다.The magneto-optical disk of the present invention for achieving the above object is a magneto-optical magnet in which a first dielectric film, a recording film, a second dielectric film, a reflective film and a protective film are sequentially stacked on a substrate so that data can be recorded, reproduced and stored. In the disc, an oxide film is formed between the recording film and the second dielectric film, and the composition of the oxide film is expressed by the formula (rare earth-transition element) 100-x (O) x .
이하, 본 발명의 구성을 첨부된 도면을 참조하여 좀 더 구체적으로 살펴보면 다음과 같다.Hereinafter, the configuration of the present invention will be described in more detail with reference to the accompanying drawings.
본 발명은 제1도에 도시된 종래의 4층구조의 기록층의 문제점인 기록시의 외부자계감도를 개선시켜 자기적인 직접기록이 가능하도록 하기 위하여, 기록층의 구조를 5층구조로 개선하여 제2도에 도시된 바와 같이 기판(11)상에 제1유전체막(12), 기록막(13), 산화막(17), 제2유전체막(14), 반사막(15) 및 보호막(16)이 순차적으로 적층된 광자기 디스크로 구성된다.The present invention improves the structure of the recording layer to a five-layer structure in order to enable magnetic direct recording by improving the external magnetic field sensitivity during recording, which is a problem of the conventional four-layer recording layer shown in FIG. As shown in FIG. 2, a first dielectric film 12, a recording film 13, an oxide film 17, a second dielectric film 14, a reflective film 15, and a protective film 16 are disposed on a substrate 11. It consists of a magneto-optical disk stacked sequentially.
본 발명의 유전체막(12, 14), 기록막(13), 반사막(15)은 종래의 구조에서 사용되는 것과 동등한 수준의 특성을 갖는 재료를 사용하며, 기록막(13)과 제2유전체막(14)의 사이에 기록막 재료를 산화시켜 입힙 산화막(7)을 삽입한 것을 특징으로 하는데, 상기 산화막(17)은 기록막(13)과는 달리 수직자화 성질을 갖지 않으며, 수평자화특성을 갖는다. 또한, 산화막(17)의 보자력은 기록막에 비해 매우 작은 것을 특징으로 한다.The dielectric films 12 and 14, the recording film 13, and the reflective film 15 of the present invention are made of a material having the same level of characteristics as those used in the conventional structure, and the recording film 13 and the second dielectric film The recording film material is oxidized between the 14 to insert the coated oxide film 7. The oxide film 17, unlike the recording film 13, does not have a vertical magnetization property and has a horizontal magnetization characteristic. Have In addition, the coercive force of the oxide film 17 is characterized by being very small compared with the recording film.
본 발명을 구현하기 위해 사용된 5층구조 기록층은 스퍼터링(sputtering)이라고 하는 박막제조공정을 사용하였으나, 본 발명에서 원하는 성질의 박막을 제조할 수만 있다면 다른 어떠한 방법을 사용하여도 본 발명의 효과를 쉽게 달성할 수 있다. 유전체막의 가장 널리 사용되는 제조방법은 Si, Al, AlSi, 또는 Zn와 같은 재료를 반응성 스퍼터링 방식에 의해 SiN, AIN, AlSiN, 또는 ZnS로 형성시키고 반사막은 Al, AlTi, AlTa, AlNi등의 재료를 스퍼터링 방식으로 제조하며, 기록막은 TbFeCo, TbFeCoCr, TbFeCoZr, GdTbFeCo등의 희토류-천이금속등의 희토류-천이금속 재료로 스퍼터링 방식으로 제조되며, 본 발명의 핵심구성요소인 산화막은 기록막과 같은 재질로 반응성 스퍼터링 방식에 의해 (희토류-천이원소계)100-xOx조성으로 제조된다. 이때, 희토류-천이금속의 재료로는 종래의 TbFeCo계, TbFeCoCr계, TbFeCoZr계, GdTbFeCo계, NdTbFeCo계등이 사용될 수 있는데, 가장 이상적인 조성범위는 다음과 같다. TbFeCo계는 Tb이 18∼26 atm%, Co가 6∼20 atm%, 그리고 나머지는 Fe로 구성되며, TbFeCoZr계는 Tb이 17∼25 atm%, Co가 6∼20 atm%, Zr이 4∼8 atm%, 그리고 나머지는 Fe로 구성되며, GdTbFeCo계는 Gd가 5∼15 atm%, Tb이 8∼16 atm%, Co가 6∼20 atm%, 및 나머지는 Fe로 구성되며, GdTbFeCo계는 Nd가 5∼15 atm%, Tb이 8∼16 atm%, Co가 6∼20 atm%, 및 나머지는 Fe로 구성된다. 상기의 산화막 조성식의 산소조성을 나타내는 X는 3∼15 atm%의 범위에서 본 발명의 효과가 나타난다. 산소의 함량, X가 3 atm%이하로 함유되면, 보자력이 기록막의 30%정도 이상이며 수평자화가 완전치 못하므로 산화막이 수직자기이방성을 갖고 있어, 기록막의 수직자기이방성을 충분히 감소시키지 못하며, 15 atm% 이상 함유되면 산화막의 보자력이 기록막의 5%이하가 되므로 산화막이 자성을 띄지 못하게 되어 기록막과의 교환결합이 이루어지지 못하게 된다. 또한, 상기 산화막의 두께는 1-15nm로서, 1nm이하이면 기록막의 자계감도를 충분히 감소시키지 못하며, 15nm이상이 되면 기록막의 기록 재생특성이 저하되는 문제점이 발생되므로 바람직하지 않다.The five-layer structure recording layer used to implement the present invention used a thin film manufacturing process called sputtering, but any other method can be used as long as the present invention can produce a thin film having a desired property. Can be easily achieved. The most widely used dielectric film is formed of Si, Al, AlSi, or Zn by SiN, AIN, AlSiN, or ZnS by reactive sputtering, and the reflective film is made of Al, AlTi, AlTa, AlNi, etc. It is manufactured by sputtering method, and the recording film is manufactured by sputtering method with rare earth-transition metal materials such as rare earth-transition metal such as TbFeCo, TbFeCoCr, TbFeCoZr, GdTbFeCo, and the oxide film, which is a key component of the present invention, is made of the same material as the recording film. It is prepared in a (rare earth-transition element) 100-x O x composition by a reactive sputtering method. At this time, as a rare earth-transition metal material, conventional TbFeCo-based, TbFeCoCr-based, TbFeCoZr-based, GdTbFeCo-based, NdTbFeCo-based, and the like may be used. The TbFeCo system is composed of Tb of 18 to 26 atm%, Co of 6 to 20 atm%, and the rest of Fe. The TbFeCoZr system of Tb is 17 to 25 atm%, Co of 6 to 20 atm%, and Zr of 4 to 20 atm%. 8 atm%, and the rest is composed of Fe, the GdTbFeCo system is composed of 5 to 15 atm% of Gd, 8 to 16 atm% of Tb, 6 to 20 atm% of Co, and the rest of Fe, GdTbFeCo system is Nd is 5-15 atm%, Tb is 8-16 atm%, Co is 6-20 atm%, and the remainder is Fe. X, which represents the oxygen composition of the oxide film composition formula, exhibits the effect of the present invention in the range of 3 to 15 atm%. When the oxygen content, X, is less than 3 atm%, the coercive force is about 30% or more of the recording film and the horizontal magnetization is incomplete, so the oxide film has vertical magnetic anisotropy, and thus the vertical magnetic anisotropy of the recording film is not sufficiently reduced. When 15 atm% or more is contained, the coercive force of the oxide film is less than 5% of the recording film, so that the oxide film is not magnetic and thus cannot be exchanged with the recording film. In addition, the thickness of the oxide film is 1-15 nm, and if it is 1 nm or less, the magnetic field sensitivity of the recording film may not be sufficiently reduced. If the thickness of the oxide film is 15 nm or more, the recording and reproducing characteristics of the recording film are deteriorated.
본 발명에서 사용된 기록막과 제2유전체막 사이의 산화막은 자성을 띄고 있으며, 박막면에 수평한 자화방향을 가지며, 보자력은 기록막에 비해 매우 적은 것을 특징으로 한다. 산화막의 이와 같은 자기적 성질은 기록막과 인접하여 있을 경우 기록막과 자기적으로 교환결합을 하게 되므로 기록막에서 제2유전체막으로 나오는 자력선을 산화막이 제한하여 기록막의 수직자기이방성 에너지를 감소시키는 역할을 행한다. 따라서, 기록막과 산화막이 자기적으로 교환결합된 상태에서 기록을 하게 되면 적은 외부기록 자계에서도 손쉽게 기록이 될 뿐만 아니라, 반자계(dimagnetization)를 감소시키므로 해서 외부자계 없이 30 dB이상으로 기록이 되는 현상이 현저하게 감소하게 된다.The oxide film between the recording film and the second dielectric film used in the present invention has magnetic properties, has a magnetization direction horizontal to the thin film surface, and the coercive force is much smaller than that of the recording film. This magnetic property of the oxide film is magnetically exchanged with the recording film when it is adjacent to the recording film. Therefore, the oxide film restricts the magnetic lines of force from the recording film to the second dielectric film to reduce the perpendicular magnetic anisotropy energy of the recording film. Play a role. Therefore, when the recording film and the oxide film are magnetically exchanged, recording is not only easily performed in a small external recording magnetic field, but also is recorded at 30 dB or more without an external magnetic field by reducing dimagnetization. The phenomenon is significantly reduced.
이하, 본 발명의 효과를 실시예 1및 비교예 1을 통하여 좀 더 구체적으로 살펴보지만, 하기 실시예에 본 발명의 범주가 한정되는 것은 아니다.Hereinafter, the effects of the present invention will be described in more detail with reference to Example 1 and Comparative Example 1, but the scope of the present invention is not limited to the following examples.
[실시예 1]Example 1
유리기판상에 반응성 스퍼터링법으로 SiN을 두께 100nm로 증착하여 제1유전체막을 형성시키고, 그 위에 스퍼터링법으로 Tb 22atm%, Fe 70atm%, Co 8atm%을 두께 20nm로 기록막을 증착하고, 산화막을(Tb22Fe70Co3)93(O)7로 두께 10nm으로 스퍼터링법으로 형성하고, 제2유전체막을 두께 31nm으로 상기 제1유전체막과 같은 방법 및 물질로 증착하고, AlTi를 Al 95 atm%, Ti 5 atm%로 스퍼터링법으로 두께 34nm의 반사막, 자외선 경화성수지로 스핀코팅법에 의해 두께 8um로 보호막을 형성하여 본 발명의 광자기 디스크를 제조하였다.SiN is deposited to a thickness of 100 nm on the glass substrate to form a first dielectric film, and a recording film is deposited to a thickness of 20 nm on Tb 22atm%, Fe 70atm%, and Co 8atm% by sputtering, and an oxide film (Tb 22 Fe 70 Co 3 ) 93 (O) 7 was formed by sputtering at a thickness of 10 nm, and the second dielectric film was deposited by the same method and material as the first dielectric film with a thickness of 31 nm. A magneto-optical disk of the present invention was prepared by forming a protective film having a thickness of 8 nm by sputtering at 5 atm% and a thickness of 8 um by spin coating with a UV curable resin.
[비교예 1]Comparative Example 1
기록막의 두께를 24.5nm, 제2유전체막의 두께를 31nm 및 산화막을 입히지 않은 것을 제외하고는 상기 실시예 1과 동일하게 하여 광자기 디스크를 제조하였다.The magneto-optical disk was manufactured in the same manner as in Example 1 except that the recording film had a thickness of 24.5 nm, the second dielectric film had a thickness of 31 nm, and no oxide film was applied.
상기 실시예 1과 비교예 1에 의해 제조된 광자기 디스크의 외부기록자계에 따른 기록재생특성을 제3도 및 제4도에 도시하였다.3 and 4 show recording and reproduction characteristics according to the external recording magnetic field of the magneto-optical disks prepared in Example 1 and Comparative Example 1. FIG.
제3도는 비교예 1의 기록층을 채용한 광자기 디스크의 외부자계에 대한 기록재생특성(CNR)을 나타낸 것으로서, 외부자계가 250 Oe(Oersted)일 때 포화되며, 또한 외부자계가 0 Oe일때도 30 dB가 넘는 기록재생특성(CNR)을 나타냈으며, 제4도는 실시예 1의 기록층 구조(5층구조)를 사용하여 저조한 디스크의 외부자계에 대한 기록재생특성을 측정한 것으로 기록재생특성이 포화되는 외부자계는 100 Oe이하이며, 외부자계 0 Oe에서의 기록재생특성은 20 dB이하인 것으로 나타났다. 따라서, 자기적인 직접기록방법을 사용하는 시스템에 본 발명의 디스크를 적용할 경우 기록을 위한 자기헤드의 사양을 100 Oe이하로 낮출 수 있게 되며, 이는 자기헤드의 소비전력을 크게 낮출 수 있을 뿐만 아니라, 자기헤드에서 발생하는 열도 크게 줄일 수 있는 효과가 있다.3 shows recording / reproducing characteristics (CNR) of the magneto-optical disk employing the recording layer of Comparative Example 1, which saturates when the external magnetic field is 250 Oe (Oersted) and also when the external magnetic field is 0 Oe. Fig. 4 shows more than 30 dB of recording / playback characteristics (CNR). Fig. 4 shows the recording / playback characteristics of a low-density disc using the recording layer structure (five-layer structure) of Example 1. This saturated external magnetic field was less than 100 Oe, and the recording and reproduction characteristics of the external magnetic field 0 Oe were less than 20 dB. Therefore, when the disc of the present invention is applied to a system using a magnetic direct recording method, the specification of the magnetic head for recording can be lowered to 100 Oe or less, which can greatly reduce the power consumption of the magnetic head. As a result, the heat generated from the magnetic head can be greatly reduced.
본 발명에 따르면, 산화막을 기록막과 자기적으로 교환결합시키므로서 기록시의 외부자계 감도를 향상시키며, 또한 고주파의 자기헤드를 사용하게 되는 자기적 직접기록방법(DOW)에 적용되는 경우에 자기헤드의 제조를 용이하게 하며, 기록막의 반자계를 최소화시키므로서 기록시 형성된 자구(domain)의 크기가 기록막의 자기특성에 의해 제한되지 않고, 레이저광이 조사되는 영역으로 결정되게 되므로 원하는 길이와 폭의 자구를 얻기가 용이하며, 또한 산화막 제조시 기록막과 같은 조성의 재료를 사용하므로써 별도의 제막공정을 사용치 않고도 디스크를 제조할 수 있으므로 제조원가를 절감할 수 있는 장점이 있다.According to the present invention, when the oxide film is magnetically exchange-coupled with the recording film, the magnetic field is improved when applied to the magnetic direct recording method (DOW), which improves the sensitivity of the external magnetic field during recording and uses a high-frequency magnetic head. It is easy to manufacture the head, and the size of the domain formed during recording by minimizing the semi-magnetic field of the recording film is not limited by the magnetic properties of the recording film. It is easy to obtain the magnetic domain of, and since the disk can be manufactured without using a separate film forming process by using a material having the same composition as the recording film in manufacturing the oxide film, the manufacturing cost can be reduced.
Claims (4)
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