# US 7,407,720 B2 · Interlayer design for magnetic media > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,720 B2 - Document ID: US7407720B2 - Status: Granted - Kind: B2 - Application number: 10/813,117 - Filed: 2004-03-31 - Published: 2005-04-21 - Granted: 2008-08-05 - Earliest claimed: 2003-10-17 - Assignees: Seagate Technology LLC - Inventors: Erol Girt; Alex Rou; John Wang - Web page: https://patentgrep.com/patent/US7407720B2 ## CPC - G11B 5/672: {having different compositions in a plurality of magnetic layers, e.g. layer compositions having differing elemental components or differing proportions of elements} - Y10T 428/265: 1 mil or less - 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) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A magnetic recording medium having a substrate, an interlayer and a magnetic layer, the interlayer having at least a first intermediary layer, a second intermediary layer and a third intermediary layer, wherein the first intermediary layer or the third intermediary layer is non-magnetic or magnetic and the second intermediary layer has a hexagonal close pack crystal structure and a property of providing RKKY coupling between the first intermediary layer and the third intermediary layer when the first intermediary layer and the second intermediary layer are magnetic layers is disclosed. ## Claims ### Claim 1 A magnetic recording medium comprising a substrate, an interlayer and a magnetic layer, the interlayer comprising at least a first intermediary layer, a second intermediary layer and a third intermediary layer, wherein the first intermediary layer or the third intermediary layer is non-magnetic and the second intermediary layer has a hexagonal close pack crystal structure, wherein the magnetic layer comprises (a) a Cr-rich layer comprising Cr and (b) a Cr-dilute layer comprising Cr, wherein the Cr-rich layer comprises a greater atomic percent Cr than the Cr-dilute layer. ### Claim 2 (depends on 1) The medium of claim 1, wherein the first intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 3 (depends on 2) The medium of claim 2, wherein the third intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 4 (depends on 3) The medium of claim 3, further comprising a non-oxidized or oxidized NiP or CoW layer on the substrate. ### Claim 5 (depends on 2) The medium of claim 2, wherein the magnetic layer comprises CoCr or an alloy of CoCr with at least one element selected from the group consisting of Pt, Ta, B, Mo, Ru, Si, Ge, Nb, Fe, Ni, Cu, Ag, Au and combinations thereof. ### Claim 6 (depends on 2) The medium of claim 2, wherein the first intermediary layer has a thickness of less than 1 nm and the second intermediary layer has a thickness of about 0.01 to 3 nm. ### Claim 7 A method of manufacturing a magnetic recording medium comprising depositing an interlayer on a substrate and depositing a magnetic layer on the interlayer, the interlayer comprising at least a first intermediary layer, a second intermediary layer and a third intermediary layer, wherein the first intermediary layer or the third intermediary layer is non-magnetic and the second intermediary layer has a hexagonal close pack crystal, wherein the magnetic layer comprises (a) a Cr-rich layer of CoCr or CoCr with one or more elements selected from the group consisting of Pt, Ta, B, Mo, Ru, Si, Ge, Nb, Fe, Ni, Cu, Ag, Au, where in Cr concentration is greater than or equal to 17 atomic %, and (b) a Cr-dilute layer of CoCr or CoCr with one or more elements selected from the group consisting of Pt, Ta, B, Mo, Ru, Si, Cu, Ag, Ge, Nb, Fe, Ni, Au, where in Cr concentration is less than 17 atomic %. ### Claim 8 (depends on 7) The method of claim 7, wherein the first intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Cu, Ag, Au, and combinations thereof, and further wherein the third intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Cu, Ag, Au, and combinations thereof. ### Claim 9 (depends on 7) The method of claim 7, wherein the first intermediary layer has a thickness of less than 1 nm and the second intermediary layer has a thickness of about 0.01 to 3 nm. ### Claim 10 (depends on 1) The medium of claim 1, wherein the second intermediary layer having a hexagonal close pack crystal structure comprises a material selected from the group consisting of Ru, Re and alloys thereof. ### Claim 11 (depends on 1) The medium of claim 1, wherein the second intermediary layer comprises at least one bcc-structured element selected from the group consisting of W, Mo, Ta, Nb, Cr, and V. ### Claim 12 (depends on 1) The medium of claim 1, wherein the second intermediary layer having a hexagonal close pack crystal structure comprises Ru or a Ru alloy that consist of over 80 at. % of Ru and the rest of elements selected from the group consisting of Ti, V, Cr, Zr, Nb, Mo, Rh, Hf, Ta, W and Ir. ### Claim 13 (depends on 1) A magnetic recording medium of claim 1 wherein the magnetic layer comprises (a) a Cr-rich layer of CoCr or CoCr with one or more elements selected from the group consisting of Pt, Ta, B, Mo, Ru, Si, Ge, Nb, Fe, Ni, Cu, Ag, Au, where in Cr concentration is greater than or equal to 17 atomic %, and (b) a Cr-dilute layer of CoCr or CoCr with one or more elements selected from the group consisting of Pt, Ta, B, Mo, Ru, Si, Cu, Ag, Ge, Nb, Fe, Ni, Au, where in Cr concentration is less than 17 atomic %. ### Claim 14 (depends on 13) The medium of claim 13, wherein the first intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 15 (depends on 13) The medium of claim 13, wherein the second intermediary layer has a hexagonal close pack crystal structure and comprises a material selected from the group consisting of Ru, Re and alloys thereof. ### Claim 16 (depends on 13) The medium of claim 13, wherein the third intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 17 (depends on 1) The medium of claim 1, wherein the first intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 18 (depends on 1) The medium of claim 1, wherein the second intermediary layer having a hexagonal close pack crystal structure comprises a material selected from the group consisting of Ru, Re and alloys thereof. ### Claim 19 (depends on 1) The medium of claim 1, wherein the third intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 20 (depends on 10) The medium of claim 10, wherein the first intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 21 (depends on 10) The medium of claim 10, wherein the second intermediary layer having a hexagonal close pack crystal structure comprises a material selected from the group consisting of Ru, Re and alloys thereof. ### Claim 22 (depends on 10) The medium of claim 10, wherein the third intermediary layer has a hexagonal close pack crystal structure and comprises Co or a Co alloy with at least one element selected from the group consisting of Cr, Pt, Ta, B, Ti, Zr, Hf, Mo, Ru, Si, Ge, Nb, Fe, Ni, Ag, Au and combinations thereof. ### Claim 23 (depends on 15) The medium of claim 15, wherein the second intermediary layer further comprises at least one bcc-structured element. ### Claim 24 (depends on 18) The medium of claim 18, wherein the second intermediary layer further comprises at least one bcc-structured element. ### Claim 25 (depends on 21) The medium of claim 21, wherein the second intermediary layer further comprises at least one bcc-structured element. ### Claim 26 (depends on 23) The medium of claim 23, wherein the at least one bcc-structured element selected from the group consisting of W, Mo, Ta, Nb, Cr, and V.