# US 2004/0072031 A1 · Magnetic recording medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2004/0072031 A1 - Document ID: US20040072031A1 - Status: Published application - Kind: A1 - Application number: 10/444,962 - Filed: 2003-05-27 - Published: 2004-04-15 - Earliest claimed: 2002-10-01 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Hoon-sang Oh; Byung-kyu Lee - Web page: https://patentgrep.com/patent/US20040072031A1 ## CPC - G11B 5/7369: {Two or more non-magnetic underlayers, e.g. seed layers or barrier layers} - 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) ## Abstract A magnetic recording medium including a magnetic recording layer and a substrate that supports the magnetic recording layer is provided. At least two underlayers including a nonmetallic underlayer are placed between the magnetic recording layer and the substrate. The perpendicular magnetic recording medium uses a double-layered or tri-layered underlayer. Accordingly, a perpendicular magnetic recording layer can have a high perpendicular magnetic anisotropic energy constant Ku due to a third underlayer and have small crystal grains and a small exchange coupling due to a second underlayer below the third underlayer. Thus, the perpendicular magnetic recording layer can have a good thermal stability, high-density recording characteristics, and excellent SNR characteristics. ## Claims ### Claim 1 A magnetic recording medium comprising: a magnetic recording layer; and a substrate that supports the magnetic recording layer, wherein at least two underlayers including a nonmetallic underlayer are placed between the magnetic recording layer and the substrate. ### Claim 2 (depends on 1) The magnetic recording medium of claim 1, wherein the magnetic recording layer is a perpendicular magnetic recording layer. ### Claim 3 (depends on 1) The magnetic recording medium of claim 1, wherein a soft magnetic layer is formed between a stack of underlayers and the substrate. ### Claim 4 (depends on 2) The magnetic recording medium of claim 2, wherein a soft magnetic layer is formed between a stack of underlayers and the substrate. ### Claim 5 (depends on 1) The magnetic recording medium of claim 1, wherein first, second, and third underlayers are included, and the first underlayer adjacent to the substrate is formed of a material selected from the group consisting of Ti, Pt, Ta, Pd, and Au or an alloy containing at least two materials selected from the group, the second underlayer is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the third underlayer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 6 (depends on 2) The magnetic recording medium of claim 2, wherein first, second, and third underlayers are included, and the first underlayer adjacent to the substrate is formed of a material selected from the group consisting of Ti, Pt, Ta, Pd, and Au or an alloy containing at least two materials selected from the group, the second underlayer is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the third underlayer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 7 (depends on 3) The magnetic recording medium of claim 3, wherein first, second, and third underlayers are included, and the first underlayer adjacent to the substrate is formed of a material selected from the group consisting of Ti, Pt, Ta, Pd, and Au or an alloy containing at least two materials selected from the group, the second underlayer is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the third underlayer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 8 (depends on 4) The magnetic recording medium of claim 4, wherein first, second, and third underlayers are included, and the first underlayer adjacent to the substrate is formed of a material selected from the group consisting of Ti, Pt, Ta, Pd, and Au or an alloy containing at least two materials selected from the group, the second underlayer is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the third underlayer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 9 (depends on 1) The magnetic recording medium of claim 1, wherein two underlayers are included, and one underlayer adjacent to the substrate is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the other underlayer adjacent to the magnetic recording layer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 10 (depends on 2) The magnetic recording medium of claim 2, wherein two underlayers are included, and one underlayer adjacent to the substrate is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the other underlayer adjacent to the magnetic recording layer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 11 (depends on 3) The magnetic recording medium of claim 3, wherein two underlayers are included, and one underlayer adjacent to the substrate is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the other underlayer adjacent to the magnetic recording layer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 12 (depends on 4) The magnetic recording medium of claim 4, wherein two underlayers are included, and one underlayer adjacent to the substrate is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the other underlayer adjacent to the magnetic recording layer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 13 (depends on 1) The magnetic recording medium of claim 1, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 14 (depends on 2) The magnetic recording medium of claim 2, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 15 (depends on 3) The magnetic recording medium of claim 3, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 16 (depends on 4) The magnetic recording medium of claim 4, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 17 (depends on 5) The magnetic recording medium of claim 5, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 18 (depends on 9) The magnetic recording medium of claim 9, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 19 A magnetic recording medium comprising: a magnetic recording layer; a substrate that supports the magnetic recording layer; and a soft magnetic underlayer placed between the magnetic recording layer and the substrate, wherein at least two underlayers including at least a nonmetallic underlayer are placed between the magnetic recording layer and the soft magnetic underlayer. ### Claim 20 (depends on 19) The magnetic recording medium of claim 19, wherein the magnetic recording layer is a perpendicular magnetic recording layer. ### Claim 21 (depends on 19) The magnetic recording medium of claim 19, wherein first, second, and third underlayers are included, and the first underlayer adjacent to the substrate is formed of a material selected from the group consisting of Ti, Pt, Ta, Pd, and Au or an alloy containing at least two materials selected from the group, the second underlayer is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the third underlayer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 22 (depends on 20) The magnetic recording medium of claim 20, wherein first, second, and third underlayers are included, and the first underlayer adjacent to the substrate is formed of a material selected from the group consisting of Ti, Pt, Ta, Pd, and Au or an alloy containing at least two materials selected from the group, the second underlayer is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the third underlayer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 23 (depends on 19) The magnetic recording medium of claim 19, wherein two underlayers are included, and one underlayer adjacent to the substrate is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the other underlayer adjacent to the magnetic recording layer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 24 (depends on 20) The magnetic recording medium of claim 20, wherein two underlayers are included, and one underlayer adjacent to the substrate is formed of a material selected from the group consisting of carbon, silicon, a silicon oxide, a silicon nitride, a metal oxide, a metal nitride, and a metal sulfide, and the other underlayer adjacent to the magnetic recording layer is formed of a material selected from the group consisting of Pt, Pd, Ru, a Pt alloy, a Pd alloy, a Ru alloy, and a Co alloy. ### Claim 25 (depends on 19) The magnetic recording medium of claim 19, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 26 (depends on 20) The magnetic recording medium of claim 20, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 27 (depends on 21) The magnetic recording medium of claim 21, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 28 (depends on 22) The magnetic recording medium of claim 22, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 29 (depends on 23) The magnetic recording medium of claim 23, wherein the total thickness of the underlayers is no more than 15 nm. ### Claim 30 (depends on 24) The magnetic recording medium of claim 24, wherein the total thickness of the underlayers is no more than 15 nm.