Magneto-optical recording medium

• US 5,476,713 A
• Filed: 08/26/1993
• Issued: 12/19/1995
• Est. Priority Date: 11/07/1990
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yoshida, Mari, Nakayama, Hiroshi, Abiko, Toru, Kishi, Takashi
• Primary Examiner(s): KILIMAN, LESZEK B
• Application Number:
  US08/112,060
• Time in Patent Office: 845 Days
• Field of Search: 428/698, 428/702, 428/704, 428/900, 428/694 ML, 428/694 RE, 428/694 NF, 428/694 XS, 428/694 DE, 428/332, 428/336, 428/694 MM, 428/694 RL
• US Class Current: 428/332
• CPC Class Codes: G11B 11/10584 characterised by the form, e.g. comprising mechanical protection elements
• CPC Class Codes: G11B 11/10586 characterised by the selection of the material
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A magneto-optical recording medium having at least two kinds of films consisting of a rare earth metal-transition metal alloy thin film and a dielectric film formed on a substrate. The dielectric film is formed by sputtering a target in an atmosphere containing at least an oxygen gas or a compound gas containing oxygen as one constitutional element. Particularly, the use of a carbon dioxide gas CO₂ or a carbon monoxide gas CO provides for an SiCON film rather than an Si₃ N₄ film. The SiCON film has a refractive index and an absorptivity almost identical with those of the Si₃ N₄ film, and has a thermal conductivity smaller than that of the Si₃ N₄ film. As a result, it has been found that the SiCON film is advantageous from the viewpoints of a magnetic field sensitivity and a film thickness.

Claims

1. A magneto-optical recording medium consisting of a substrate, a first dielectric film formed on the surface of said substrate, a rare earth metal-transition metal alloy film formed on said first dielectric film, a rare earth film formed on said rare earth metal-transition metal alloy film, a second dielectric film formed on said rare earth film and, a reflecting film formed on said second dielectric film, and said first and second dielectric films have a composition of Si_x C_y O_z N_v, where x, y, z, and v satisfy the following conditions:

space="preserve" listing-type="equation">0.40≦

x≦

0.60

space="preserve" listing-type="equation">0.05≦

y≦

0.20

space="preserve" listing-type="equation">0.05≦

z≦

0.30

space="preserve" listing-type="equation">0.10≦

v≦

0.30

space="preserve" listing-type="equation">x+y+z+v=1.

2. The magneto-optical recording medium according to claim 1, wherein said first and second dielectric film are formed by sputtering a silicon target in an atmosphere containing a gas composed of oxygen and carbon and a nitrogen gas.

3. The magneto-optical recording medium according to claim 1, wherein said first dielectric film has thickness of 600-900 angstroms and said second dielectric film has a thickness of 250 to 350 angstroms.