# US 2010/0165504 A1 · Method of producing magnetic recording medium, and magnetic recording and reading device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0165504 A1 - Document ID: US20100165504A1 - Status: Published application - Kind: A1 - Application number: 12/600,416 - Filed: 2008-06-17 - Published: 2010-07-01 - Earliest claimed: 2007-06-19 - Assignees: Showa Denko K.K. - Inventors: Masato Fukushima; Akira Sakawaki; Yasumasa Sasaki - Web page: https://patentgrep.com/patent/US20100165504A1 ## CPC - G11B 5/855: Coating only part of a support with a magnetic layer - H01F 41/34: in patterns, e.g. by lithography - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract The present invention aims to provide a method of producing a magnetic recording medium which is a method of producing a magnetic recording medium having a magnetically-separated magnetic recording pattern, the method including: forming a magnetic layer on a non-magnetic substrate; then exposing a surface of the magnetic layer partially to reactive plasma, or a reactive ion generated in the plasma to amorphize the portion of the magnetic layer. ## Claims ### Claim 1 A method of producing a magnetic recording medium having a magnetically-separated magnetic recording pattern, the method comprising: forming a magnetic layer over a non-magnetic substrate; and then exposing a surface of the magnetic layer partially to reactive plasma, or a reactive ion generated in the plasma to amorphize the portion of the magnetic layer and to modify the magnetic properties of the portion whereby a magnetically-separated magnetic recording pattern is formed. ### Claim 2 (depends on 1) The method of producing a magnetic recording medium according to claim 1, wherein the magnetization magnitude of the portion of the magnetic layer which is exposed to reactive plasma is adjusted to 75% or less of the original magnetization magnitude thereof in modifying the magnetic properties. ### Claim 3 (depends on 1) The method of producing a magnetic recording medium according to claim 1, wherein the coercive force of the portion of the magnetic layer which is exposed to reactive plasma is adjusted to 50% or less of the original coercive force thereof in modifying the magnetic properties. ### Claim 4 (depends on 1) The method of producing a magnetic recording medium according to claim 1, wherein the reactive plasma is plasma which includes an oxygen ion generated by introducing an oxygen gas. ### Claim 5 (depends on 1) The method of producing a magnetic recording medium according to claim 1, wherein the reactive plasma includes a halogen ion. ### Claim 6 (depends on 5) The method of producing a magnetic recording medium according to claim 5, wherein the portion of the magnetic layer which is exposed to the halogen ion does not substantially include a halide of a substance constituting the magnetic layer. ### Claim 7 (depends on 5) The method of producing a magnetic recording medium according to claim 5, wherein the reactive plasma includes oxygen and a halogen. ### Claim 8 (depends on 5) The method of producing a magnetic recording medium according to claim 5, wherein the magnetic layer is exposed to plasma including oxygen, and then the magnetic layer is exposed to plasma including a halogen in exposing the surface of the magnetic layer partially to reactive plasma to modify magnetic properties of the portion of the magnetic layer. ### Claim 9 (depends on 1) The method of producing a magnetic recording medium according to claim 1 further comprising injecting an ion partially to the surface of the magnetic layer before exposing the surface of the magnetic layer partially to reactive plasma. ### Claim 10 (depends on 9) The method of producing a magnetic recording medium according to claim 9, wherein the injected ion is argon or nitrogen. ### Claim 11 (depends on 5) The method of producing a magnetic recording medium according to claim 5, wherein the halogen ion is a halogen ion which is formed by introducing into the reactive plasma at least one halogenated gas selected from the group consisting of CF4, SF6, CHF3, CCl4, and KBr. ### Claim 12 (depends on 5) The method of producing a magnetic recording medium according to claim 5, wherein the halogen ion is an F ion. ### Claim 13 (depends on 1) The method of producing a magnetic recording medium according to claim 1, wherein, after the magnetic layer is formed over the non-magnetic substrate, a resist pattern for forming the magnetically-separated magnetic recording pattern is formed on the surface of the magnetic layer, and then, a portion which is not covered with the resist pattern is exposed to the reactive plasma to modify magnetic properties of the portion, thereby forming the magnetically-separated magnetic recording pattern. ### Claim 14 (depends on 1) The method of producing a magnetic recording medium according to claim 1, wherein a resist pattern is formed after a protective layer is formed on the magnetic layer. ### Claim 15 (depends on 1) The method of producing a magnetic recording medium according to claim 1, wherein the magnetic recording pattern is a perpendicular magnetic recording pattern. ### Claim 16 (depends on 1) A magnetic recording and reading device, comprising: the magnetic recording medium produced by the method of producing a magnetic recording medium according to claim 1; an actuating device which actuates the magnetic recording medium in the recording direction; a magnetic head which includes a recording part and a reading part; a system which moves the magnetic head relatively to the magnetic recording medium; and a recording and reading signal-processing unit which inputs a signal to the magnetic head and which reads an output signal from the magnetic head.