Magneto-optical recording element

• US 4,680,742 A
• Filed: 07/08/1985
• Issued: 07/14/1987
• Est. Priority Date: 07/09/1984
• Status: Expired due to Term

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Yamada, Takashi, Maeda, Takashi, Arimune, Hisao
• Primary Examiner(s): Cardillo, Raymond F.
• Assistant Examiner(s): Nguyen, Hoa T.
• Application Number:
  US06/752,927
• Time in Patent Office: 736 Days
• Field of Search: 369/13, 369/14, 427/38, 427/39, 427/131, 156/643, 430/945, 430/961, 428/64, 428/65
• US Class Current: 369/13.35
• CPC Class Codes: G03G 5/16 Layers for recording by changing the magnetic properties, e.g. for Curie-point-writing
• CPC Class Codes: G11B 11/10586 characterised by the selection of the material
• CPC Class Codes: G11B 11/10591 for improving write-in properties, e.g. Curie-point temperature
• CPC Class Codes: G11B 5/7368 Non-polymeric layer under the lowermost magnetic recording layer base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/73923 Organic polymer substrates
• CPC Class Codes: Y10S 430/146 Laser beam

Abstract

In a magneto-optical recording element comprising a substrate, a magnetic layer and a dielectric layer, the dielectric layer is formed by deposition of a composition comprising Si₃ N₄ and a refractive index-improving agent such as Al₂ O₃ or Y₂ O₃. This dielectric layer has a high refractive index and the enhancement effect is improved. Moreover, this dielectric layer is excellent in the adhesion and resistance characteristics.

Claims

1. A magneto-optical recording element comprising a substrate, a dielectric layer containing silicon nitride and a magnetic layer for magneto-optical recording having an axis of easy magnetization perpendicular to the film surface thereof, wherein

the dielectric layer consists of a deposition film formed of a composition comprising silicon nitride and an agent for improving the refractive index of silicon nitride and the dielectric layer has a refractive index of at least 2.15, and

the deposition film is formed of a composition comprising 0.1 to 5.0 mole% of alumina or aluminum nitride and 0.1 to 3.0 mole% of an oxide or nitride of a rare earth element, with the balance being silicon nitride.

4. A magneto-optical recording element as set forth in claim 1, wherein the substrate is composed of a transparent plastic material.

5. A magneto-optical recording element as set forth in claim 1, wherein the magnetic layer is composed of an amorphous alloy magnetic material.

6. A magneto-optical recording element as set forth in claim 1, wherein the element has a layer structure comprising the substrate, the magnetic layer formed on the substrate and the dielectric layer formed on the magnetic layer.

7. A magneto-optical recording element as set forth in claim 1 wherein the element has a layer structure comprising the substrate, the dielectric layer formed on the substrate and the magnetic layer formed on the dielectric layer.

8. A magneto-optical recording element as set forth in claim 1 wherein the element has a layer structure comprising the substrate, a first dielectric layer formed on the substrate, the magnetic layer formed on the first dielectric layer and a second dielectric layer formed on the magnetic layer.

9. A magneto-optical recording element as set forth in claim 1 wherein the dielectric layer has a refractive index of 2.15 to 3.5.

2. A magneto-optical recording element comprising a substrate, a dielectric layer containing silicon nitride, and a magnetic layer for magneto-optical recording having an axis of easy magnetization perpendicular to the film surface thereof, wherein the dielectric layer is a deposition film consisting essentially of a composition comprising silicon nitride and a refractive index-improving agent selected from the group consisting of single elements, oxides, nitrides, sulfides and silicides of elements of the groups IIIa, IVa, VIa, IIb, IIIb, IVb and VIb of the Periodic Table, said refractive index-improving agent being present in an amount of 0.5 to 8.0 mole% based on the composition, said dielectric layer having a refractive index greater than 2.15.

3. A magneto-optical recording element as set forth in claim 2, wherein the refractive index-improving agent is at least one member selected from the group consisting of Al, Ti, Si, Ge, Al₂ O₃, Y₂ O₃, La₂ O₃, CeO₂, Bi₂ O₃, GeO₂, ZrO₂, CdO, Cr₂ O₃, SnO₂, PbO, AlN, TiN, YN, ZnS, Sb₂ S₃, TiSi₂, and YSi₂.