KR950003181B1 - Optical-magnato medium - Google Patents

Optical-magnato medium Download PDF

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KR950003181B1
KR950003181B1 KR1019880014104A KR880014104A KR950003181B1 KR 950003181 B1 KR950003181 B1 KR 950003181B1 KR 1019880014104 A KR1019880014104 A KR 1019880014104A KR 880014104 A KR880014104 A KR 880014104A KR 950003181 B1 KR950003181 B1 KR 950003181B1
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magneto
optical
recording medium
layer
optical recording
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KR1019880014104A
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KR900006923A (en
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김진홍
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주식회사금성사
최근선
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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
    • 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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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)

Abstract

The material of recording media is made by using amorphous RE-TN alloy layer, (RbDeCo)1-xAx which has vertical magnetic axes to the face of thin film. A is one or more elements of light rare-earth elements such as Ce, Pr, Nd, Pm, Sm and Eu, and x is 0<x<0.2.

Description

광자기 기록매체Magneto-optical recording media

제 1 도는 통상적인 3층막 구조의 광자기 기록매체의 구성을 보인 종단면도.1 is a longitudinal sectional view showing the configuration of a conventional magneto-optical recording medium having a three-layer film structure.

제 2 도는 통상적인 4층막 구조의 광자기 기록매체의 구성을 보인 종단면도.2 is a longitudinal sectional view showing the configuration of a conventional magneto-optical recording medium having a four-layer film structure.

제 3 도는 본 발명에 의한 광자기 기록매체의 일실시예인(Tb26fe59Co15)l-xPrx의 갑에 따른 Kerr회전각을 보인 도표.3 is a diagram showing the Kerr rotational angle according to the value of Tb 26 fe 59 Co 15 lx Pr x which is an embodiment of the magneto-optical recording medium according to the present invention.

* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings

1 : 보호층 2 : 기록층1: protective layer 2: recording layer

3 : anti-reflection층 4 : 유전체층3: anti-reflection layer 4: dielectric layer

5 : 반사층 6 : 기판5 reflective layer 6 substrate

본 발명은 광자기 기록매체에 관한 것으로, 특히 매체의 자기 광학적 효과를 향상시켜 기록매체에서 충분한 신호를 얻는 동시에 S/N비를 향상시킬 수 있도록 한 광자기 기록매체에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium, and more particularly, to an magneto-optical recording medium capable of enhancing the magneto-optical effect of the medium to obtain a sufficient signal from the recording medium and to improve the S / N ratio.

일반적으로 박막면에 수직한 자화용이축(acis of easy magnetization)을 갖는 RE-TM계 합금은 스퍼터링(sputtering) 또는 진공증착의 방법으로 제작하여 광자기 기록매체로 이용하며, 반전자성 결합(antiferromagnetic coupling)을 하는 희토류(RE)와 천이류(TM)는 그 조성 및 제작방법에 자기적, 광학적 특성의 큰 차이를 보이고 있다.Generally, RE-TM-based alloys having an acis of easy magnetization perpendicular to the thin film surface are manufactured by sputtering or vacuum deposition and used as a magneto-optical recording medium. Anti-ferromagnetic coupling Rare Earth (RE) and Transition (TM), which show), show a large difference in magnetic and optical properties in their composition and manufacturing method.

상기 2원계 RE-TM합금으로서는 GdCo, GdFe, TbFe, TbCo, DyFe등이 알려지고 있으며, GdCo 또는 GdFe의 경우에는 상온에서의 보자력이 100-500 Oe로 작기 때문에 기록된 비트(bit)의 안정도가 낮게 되는 단점이 있었다.As the binary RE-TM alloy, GdCo, GdFe, TbFe, TbCo, DyFe and the like are known, and in the case of GdCo or GdFe, the coercivity at room temperature is small at 100-500 Oe, so the stability of the recorded bits is low. There was a disadvantage of being low.

또한 TbFe, TbCo의 경우에는 보자력은 충분히 크지만 광학적 효과, 즉 Kerr회전각이 작으므로 큰 신호를 얻을 수 없는 단점이 있었다.In addition, in the case of TbFe and TbCo, the coercive force is large enough, but the optical effect, that is, the Kerr rotation angle is small, so that a large signal cannot be obtained.

따라서 상기한 두가지의 단점을 보충할 수 있는 3원게합금인 GdTbFe 또는 TbFeCo등을 기록매체에 사용하고 있다.Therefore, GdTbFe or TbFeCo, which is a three-membered alloy that can compensate for the above two drawbacks, is used for the recording medium.

이러한 3원계 기록매체는 제 1 도와 같이 보호층(1), 기록층(2), anti-feflection층(3), 기판(6)으로 구성되는 3층막 구조와, 제 2 도와 같이 보호층(1), 기록층(2), 유전체층(4), 반사층(5), 기판(6)등으로 구성되는 4층막 구조가 일반적이다.This ternary recording medium has a three-layer film structure consisting of a protective layer 1, a recording layer 2, an anti-feflection layer 3, and a substrate 6 as in the first diagram, and a protective layer 1 as in the second diagram. ), A four-layer film structure composed of a recording layer 2, a dielectric layer 4, a reflective layer 5, a substrate 6 and the like is common.

이와 같은 종래의 광자기 기록매체에 레이저광을 집광시키면, 기록매체는 온도가 상승되고, 보자력이 작아지게 된다.By condensing laser light on such a conventional magneto-optical recording medium, the recording medium rises in temperature and the coercivity decreases.

이때 그 보자력이상의 오부장을 가하게 되면, 자화의 방향이 외부장의 방향으로 반전되어 기록된다.At this time, if a misleading length greater than the coercive force is applied, the direction of magnetization is inverted in the direction of the external field and recorded.

이와 같은 경우 상온에서 기록된 비트의 안정을 위하여 보자력은 충분히 커야 한다.In this case, the coercivity must be large enough to stabilize the recorded bits at room temperature.

이와 같이 하여 기록된 정보를 읽는 방법으로는 자기광학적 효과, 즉 반사시 또는 투과시에 편광의 회전이 일어나는 Kerr 또는 Faraday효과등을 이용하게 된다.As a method of reading the recorded information in this way, a magneto-optical effect, that is, a Kerr or Faraday effect in which rotation of polarization occurs upon reflection or transmission, is used.

그러나 이와 같은 종래의 광자기 기록매체로 이용되는 GdTbFe 또는 TbFeCo등은 상온에서 충분한 보자력으로 기록된 비트의 안정도에는 문제가 없으나, 충분히 큰 신호를 얻지 못하는 어려움이 있었다.However, GdTbFe or TbFeCo, which is used as a conventional magneto-optical recording medium, has no problem in the stability of bits recorded with sufficient coercivity at room temperature, but has difficulty in obtaining a sufficiently large signal.

상기한 바와 같은 매질에서 얻을 수 있는 Kerr효과에 의한 편광각의 회전도 0.3°정도로 작다.The rotation of the polarization angle due to the Kerr effect obtained in the medium as described above is as small as about 0.3 °.

본 발명의 목적은, 기록된 정보를 읽을 때 자기광학적 효과를 크게하여 큰 신호를 얻을 수 있고, S/N비를 증대시킬 수 있도록 한 광자기 기록매체를 제공하려는 것이다.It is an object of the present invention to provide a magneto-optical recording medium capable of obtaining a large signal by increasing the magneto-optical effect when reading recorded information, and increasing the S / N ratio.

이하 본 발명에 의한 광자기 기록매체를 상세히 설명한다.Hereinafter, the magneto-optical recording medium according to the present invention will be described in detail.

본 발명은 광자기 기록매체인 Re-TM합금 중 자기적, 광학적으로 비교적 특성이 좋은 것으로 알려진 TbFeCo에 Cd보다 가벼운 희토류인 Ce, Pr, Nd, Pm, Sm, Eu등을 첨가함으로써 안정된 자기적 특성위에 광학적 효과를 증대시킨 것이다.The present invention provides stable magnetic properties by adding Ce, Pr, Nd, Pm, Sm, Eu, etc., which is lighter than Cd, to TbFeCo, which is known to have relatively good magnetic and optical properties among Re-TM alloys. The optical effect is increased above.

즉, 본 발명에서는 박막면에 대하여 수직한 방향의 자기용이축을 갖는 비정질 RE-TM합금층(TbFeCo)l-xAx를 그 조성으로 함을 특징으로 하는 광자기 기록매체(여기서, A는 Ce, Pr, Nd, Pm, Sm, Eu등의 가벼운 희토류 중의 어느 하나 또는 2이상의 복수개 원소이다)를 제공한다.That is, in the present invention, an amorphous magnetic RE-TM alloy layer (TbFeCo) lx A x having a magnetic easy axis in a direction perpendicular to the thin film surface is composed of a magneto-optical recording medium, wherein A is Ce, Pr , Nd, Pm, Sm, Eu, any one of light rare earths, or two or more elements.

상기한 바와 같이, 가벼운 희토류는 천이류 금속들과 강자성 결합(ferromagnetic coupling)을 하고, 무거운 희토류, 즉 Cd, Tb, Dy등은 반강자성 결합은 한다.As described above, light rare earths have ferromagnetic coupling with the transition metals, and heavy rare earths, Cd, Tb, Dy, etc., have antiferromagnetic couplings.

또한 가벼운 희토류는 무거운 희토류에 비하여 Fe나 Co와 더불어 광자기적 효과에 더 큰 기여를 하게 되는데 그 이유는 무거운 희토류인 4f각의 전자는 광학적 효과에 기여하지 못하나 가벼운 희토류의 4f각의 전자는 천이류의 3d각 전자와 더불어 광학적 효과에 기여하기 때문이다.In addition, light rare earths contribute more to the magneto-optical effect together with Fe or Co than heavy rare earths because 4f angle electrons, which are heavy rare earths, do not contribute to optical effects, but 4f angle electrons of light rare earths are transitions. This is because the 3d angle of the electron contributes to the optical effect.

상기한 바와 같은 본 발명의 광자기 기록매체를 스퍼터링방법으로 만들 경우, 모든 원소의 합금으로 만든 복합원소 타겟(Target)으로 박막을 제조하는 방법과, 모든 원소를 각각의 티켓으로 하여 멀티 타켓으로부터 Co-스퍼터링으로 박막을 제조하는 방법이 있다.When the magneto-optical recording medium of the present invention as described above is made by the sputtering method, a method of manufacturing a thin film with a composite element target made of an alloy of all the elements, and Co from a multi-target with all the elements as a ticket There is a method of manufacturing a thin film by sputtering.

제 3 도는 본 발명의 일실시예로서(Tb26Fe59Co15)l-xPrx에서 x의 변화에 따른 Kerr회전각을 보인 것으로 Co-스퍼터링으로 1000Å정도의 두께로 박막을 제조하였을 경우의 Kerr회전각을 보이고 있다.3 shows Kerr rotation angle according to the change of x in lx Pr x as an embodiment of the present invention (Tb 26 Fe 59 Co 15 ), and Kerr rotation when the thin film is manufactured to a thickness of about 1000 μs by Co-sputtering Is showing the angle.

실험에 의하면, (Tb28Fe59Co15)l-xPrx에서 x가 약 0.05인 경우에는 Kerr회전각이 가장 큰 결과를 얻을 수 있었고, 0.2인 경우에는 처음 0의 경우와 동일한 Kerr회전각을 얻을 수 있었다.According to the experiment, Kerr rotation angle can be obtained when (Tb 28 Fe 59 Co 15 ) lx Pr x is about 0.05, and Kerr rotation angle is the same as that of the first 0 in case of 0.2 Could.

즉, 0＜x＜0.2인 경우에서는 Pr이 포함되지 않은 경우보다 큰 Kerr회전각을 보임을 알 수 있다.That is, in the case of 0 <x <0.2, it can be seen that Kerr rotation angle is larger than Pr is not included.

참고로 본 발명의 실험에서는 얇은 기록층을 투과한 빛이 다중반사를 하는 경우, 광학적 효과를 커지나 반사도는 줄어드는 4층막 구조가 아니라 상기한 문제점이 배제되는 3층막의 구조로 제작하였다.For reference, in the experiments of the present invention, when the light transmitted through the thin recording layer is multi-reflected, the optical effect is increased, but the four-layer film structure is reduced, but the reflectivity is reduced.

또한 본 발명에서는 상기 Pr만으로 국한되는 것은 아니며, Ce, Nd, Sm, Eu등의 가벼운 희토류를 사용할 수 있는 것이다.In addition, the present invention is not limited to the above Pr, and light rare earths such as Ce, Nd, Sm, and Eu can be used.

이상과 같이 본 발명의 광자기 기록매체는 기록된 정보를 읽을 때 자기광학적 효과를 크게 할 수 있으므로 큰 신호를 얻을 수 있으며, 이 경우 S/N비가 향상되는 효과를 얻을 수 있는 것이다.As described above, the magneto-optical recording medium of the present invention can increase the magneto-optical effect when reading the recorded information, so that a large signal can be obtained. In this case, the S / N ratio can be improved.

Claims (1)

박막면에 대하여 수직한 방향의 자기용이축을 갖는 비정질 RE-TN합금층 (TbDeCo)l-xAx를 그 조성으로 함을 특징으로 하는 광자기 기록매체, 여기서 A는 Ce, Pr, Nd, Pm, Eu등의 가벼운 희토류중에서 어느 하나 또는 2이상의 복수개 원소이고, x는 0＜x＜0.2이다.A magneto-optical recording medium having a composition of amorphous RE-TN alloy layer (TbDeCo) lx A x having a magnetic easy axis in a direction perpendicular to the thin film surface, wherein A is Ce, Pr, Nd, Pm, Eu It is any one or two or more elements among light rare earths, etc., and x is 0 <x <0.2.
KR1019880014104A 1988-10-28 1988-10-28 Optical-magnato medium KR950003181B1 (en)

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