# US 7,609,490 B2 · Magnetoresistive device, thin film magnetic head, head gimbal assembly, head arm assembly, magnetic disk apparatus, synthetic antiferromagnetic magnetization pinned layer, magnetic memory cell, and current sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,490 B2 - Document ID: US7609490B2 - Status: Granted - Kind: B2 - Application number: 11/490,112 - Filed: 2006-07-21 - Published: 2007-01-25 - Granted: 2009-10-27 - Earliest claimed: 2005-07-22 - Assignees: TDK Corporation - Inventors: Tomohito Mizuno; Daisuke Miyauchi - Web page: https://patentgrep.com/patent/US7609490B2 ## CPC - G11B 5/3909: {Arrangements using a magnetic tunnel junction} - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - G01R 33/093: {using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00)} - G11B 5/3929: {Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding} - G11C 11/16: using elements in which the storage effect is based on magnetic spin effect - G11B 2005/3996: {large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices} - 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) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G11C: STATIC STORES (semiconductor memory devices H10B) ## Abstract An MR device includes a magnetization pinned film having a nonmagnetic intermediate layer positioned on the opposite side of a magnetization free layer while sandwiching a nonmagnetic spacer layer and made of RuCu. In the case of passing read current in the stacking direction via lower and upper electrodes, decrease in a resistance change amount caused by a second magnetization pinned layer can be suppressed. Further, a first magnetization pinned layer and the second magnetization pined layer which are thicker can be antiferromagnetically coupled to each other in magnetic fields in a wider range. Thus, both increase in the resistance change amount and magnetic field stability can be achieved. Therefore, while maintaining stable operations by reducing the influence of external noise, the invention can address higher recording density by the increase in the resistance change amount as a whole. ## Claims ### Claim 1 A magnetoresistive device comprising: a magnetization free layer whose magnetization direction changes according to an external magnetic field; a nonmagnetic spacer layer which is in contact with one of faces of the magnetization free layer; a synthetic antiferromagnetic pinned layer provided on the side opposite to the magnetization free layer, of the nonmagnetic spacer layer, the synthetic antiferromagnetic pinned layer including, in order from the side of the magnetization free layer, a first magnetization pinned layer whose magnetization direction is pinned in a predetermined direction, a nonmagnetic intermediate layer made of a ruthenium copper alloy (RuCu), and a second magnetization pinned layer whose magnetization direction is pinned opposite to the magnetization direction of the first magnetization pinned layer; and a pair of electrode layers provided on both sides, in a stacking direction orthogonal to a stack surface, of a lamination which is configured of the synthetic antiferromagnetic pinned layer, the nonmagnetic spacer layer and the magnetization free layer, the pair of electrode layers providing the lamination with read current in the stacking direction, wherein the first magnetization pinned layer includes a first adjacent layer having a magnetic thickness of 367 kA to 1,312 kA and forming an interface with the nonmagnetic intermediate layer, the second magnetization pinned layer includes a second adjacent layer having a magnetic thickness of 230 kA to 1,175 kA and forming an interface with the nonmagnetic intermediate layer, and the nonmagnetic intermediate layer is made of a ruthenium copper alloy containing ruthenium (Ru) in a range from 60 atom percent (at %) to 85 atom percent (at %). ### Claim 2 (depends on 1) The magnetoresistive device according to claim 1, wherein the first and second adjacent layers are made of a cobalt iron alloy (CoFe) containing cobalt (Co) in a range from 70 atom percent (at %) to 100 atom percent (at %), or made of cobalt. ### Claim 3 (depends on 1) The magnetoresistive device according to claim 1, wherein the nonmagnetic intermediate layer has an exchange coupling constant of 0.8×10−3 J/m2 or larger and has a thickness of 0.6 nm or more. ### Claim 4 (depends on 1) A thin film magnetic head comprising a magnetoresistive device according to claim 1. ### Claim 5 (depends on 1) A head gimbal assembly comprising: a magnetic head slider having, on one side thereof, a thin film magnetic head having a magnetoresistive device according to claim 1; and a suspension whose one end is to be provided with the magnetic head slider. ### Claim 6 (depends on 1) A head arm assembly comprising: a magnetic head slider having, on one side thereof, a thin film magnetic head having a magnetoresistive device according to claim 1; a suspension whose one end is to be provided with the magnetic head slider; and an arm supporting the other end of the suspension. ### Claim 7 (depends on 1) A magnetic disk apparatus comprising a magnetic recording medium and a head arm assembly, wherein the head arm assembly includes: a magnetic head slider having, on one side thereof, a thin film magnetic head having a magnetoresistive device according to claim 1; a suspension whose one end is to be provided with the magnetic head slider; and an arm supporting the other end of the suspension. ### Claim 8 A magnetoresistive device comprising: a magnetization free layer whose magnetization direction changes according to an external magnetic field; a nonmagnetic spacer layer which is in contact with one of faces of the magnetization free layer; a synthetic antiferromagnetic pinned layer provided on the side opposite to the magnetization free layer, of the nonmagnetic spacer layer, the synthetic antiferromagnetic pinned layer including, in order from the side of the magnetization free layer, a first magnetization pinned layer whose magnetization direction is pinned in a predetermined direction, a nonmagnetic intermediate layer made of a ruthenium copper alloy (RuCu), and a second magnetization pinned layer whose magnetization direction is pinned opposite to the magnetization direction of the first magnetization pinned layer; and a pair of electrode layers provided on both sides, in a stacking direction orthogonal to a stack surface, of a lamination which is configured of the synthetic antiferromagnetic pinned layer, the nonmagnetic spacer layer and the magnetization free layer, the pair of electrode layers providing the lamination with read current in the stacking direction, wherein the first magnetization pinned layer includes a first adjacent layer having a magnetic thickness of 367 kA to 1,312 kA and forming an interface with the nonniagnetic intermediate layer, the second magnetization pinned layer includes a second adjacent layer having a magnetic thickness of 230 kA to 1,175 kA and forming an interface with the nonmagnetic intermediate layer, and the nonmagnetic intermediate layer is made of a ruthenium copper alloy containing ruthenium (Ru) in a range from 34 atom percent (at %) to 85 atom percent (at %), and has a thickness of 0.6 nm to 1.0 nm. ### Claim 9 (depends on 8) The magnetoresistive device according to claim 8, wherein the nonmagnetic intermediate layer has an exchange coupling constant of 0.8×10−3 J/m2 or larger ### Claim 10 (depends on 8) A thin film magnetic head comprising a magnetoresistive device according to claim 8. ### Claim 11 (depends on 8) A head gimbal assembly comprising: a magnetic head slider having, on one side thereof, a thin film magnetic head having a magnetoresistive device according to claim 8; and a suspension whose one end is to be provided with the magnetic head slider. ### Claim 12 (depends on 8) A head arm assembly comprising: a magnetic head slider having, on one side thereof, a thin film magnetic head having a magnetoresistive device according to claim 8; a suspension whose one end is to be provided with the magnetic head slider; and an arm supporting the other end of the suspension. ### Claim 13 (depends on 8) A magnetic disk apparatus comprising a magnetic recording medium and a head arm assembly, wherein the head arm assembly includes: a magnetic head slider having, on one side thereof, a thin film magnetic head having a magnetoresistive device according to claim 8; a suspension whose one end is to be provided with the magnetic head slider; and an arm supporting the other end of the suspension.