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Magneto-Sensitive Wire, Magneto-Impedance Element and Magneto-Impedance Sensor

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Magneto-Sensitive Wire, Magneto-Impedance Element and Magneto-Impedance Sensor (19) TZZ Z _T (11) EP 2 276 082 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: G01R 33/06 (2006.01) H01L 43/08 (2006.01) 22.06.2016 Bulletin 2016/25 (86) International application number: (21) Application number: 09724160.8 PCT/JP2009/001316 (22) Date of filing: 25.03.2009 (87) International publication number: WO 2009/119081 (01.10.2009 Gazette 2009/40) (54) MAGNETO-SENSITIVE WIRE, MAGNETO-IMPEDANCE ELEMENT AND MAGNETO-IMPEDANCE SENSOR MAGNETEMPFINDLICHER DRAHT, MAGNETIMPEDANZELEMENT UND MAGNETIMPEDANZSENSOR FIL MAGNÉTO-SENSIBLE, ÉLÉMENT À MAGNÉTO-IMPÉDANCE ET CAPTEUR À MAGNÉTO-IMPÉDANCE (84) Designated Contracting States: • RAKHMANOV A A ET AL: "Study of surface AT BE BG CH CY CZ DE DK EE ES FI FR GB GR magnetic structure in Co-based amorphous HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL microwires by means of off-diagonal PT RO SE SI SK TR magnetoimpedance effect", JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, (30) Priority: 28.03.2008 JP 2008085878 ELSEVIER SCIENCE PUBLISHERS, AMSTERDAM, NL, vol. 300, no. 1, 1 May 2006 (43) Date of publication of application: (2006-05-01), pages E37-E40, XP024984169, 19.01.2011 Bulletin 2011/03 ISSN: 0304-8853, DOI: 10.1016/J.JMMM.2005.10.142 [retrieved on (73) Proprietor: Aichi Steel Corporation 2006-05-01] Aichi 476-8666 (JP) • PHAN ET AL: "Giant magnetoimpedance materials: Fundamentals and applications", (72) Inventors: PROGRESS IN MATERIALS SCIENCE, • HONKURA, Yoshinobu PERGAMONPRESS, GB, vol.53, no.2, 1 February Aichi 476-8666 (JP) 2008 (2008-02-01), pages 323-420, XP022492050, • YAMAMOTO, Michiharu ISSN: 0079-6425, DOI: Aichi 476-8666 (JP) 10.1016/J.PMATSCI.2007.05.003 • HAMADA, Norihiko • YOSHINOBU HONKURA ET AL.: ’MI Sensor o Aichi 476-8666 (JP) Tsukatta Keitai Denwa-yo Denshi Compass no • SHIMODE, Akihiro Kaihatsu’ JOURNAL OF MAGNETICS SOCIETY Aichi 476-8666 (JP) OF JAPAN vol. 27, no. 11, 01 November 2003, pages 1063 - 1068, XP008143001 (74) Representative: Kuhnen & Wacker • FREIJO J J ET AL: "Matteucci and inverse Patent- und Rechtsanwaltsbüro Wiedemann effects in amorphous wires with Prinz-Ludwig-Straße 40A enhanced circumferential domains", JOURNAL 85354 Freising (DE) OF APPLIED PHYSICS, AMERICAN INSTITUTE OF PHYSICS, 2 HUNTINGTON QUADRANGLE, (56) References cited: MELVILLE, NY 11747, vol. 85, no. 8, 15 April 1999 EP-A1- 1 146 346 EP-A1- 1 528 402 (1999-04-15) , pages 5450-5452, XP012047473, WO-A1-2005/019851 JP-A- 2002 374 016 ISSN: 0021-8979, DOI: 10.1063/1.369972 JP-A- 2006 300 906 JP-A- 2009 031 263 Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 2 276 082 B1 Printed by Jouve, 75001 PARIS (FR) (Cont. next page) EP 2 276 082 B1 • MOHRI KET AL: "Phase Modulation Device Using • CHIRIAC H ET AL: "Effect of Mo and Nb additions Amorphous Short Wire", IEEE TRANSLATION on the magnetic properties of CoFeSiB JOURNAL ON MAGNETICS IN JAPAN, IEEE INC, amorphous wires", JOURNAL OF NEW YORK, US, vol. 6, no. 6, 1 November 1994 NON-CRYSTALLINE SOLIDS, NORTH-HOLLAND (1994-11-01), pages 61-65, XP011231235, ISSN: PHYSICS PUBLISHING. AMSTERDAM, NL, vol. 0882-4959 250-252, 1 August 1999 (1999-08-01), pages • CHEN D-X ET AL: "Circular susceptibilities of 762-765, XP004183357, ISSN: 0022-3093, DOI: CoFeSiB amorphous wires determined by 10.1016/S0022-3093(99)00175-1 inductance and second harmonic longitudinal • ZHAO Z J ET AL: "Structure and magnetic magnetization", JOURNAL OF APPLIED properties of iron/cobalt-based glass-covered PHYSICS, AMERICAN INSTITUTE OF PHYSICS, 2 microwires", PHYSICA SCRIPTA, INSTITUTE OF HUNTINGTON QUADRANGLE, MELVILLE, NY PHYSICS PUBLISHING, BRISTOL, GB, vol. 2007, 11747, vol. 93, no. 10, 15 May 2003 (2003-05-15), no. T129, 1 December 2007 (2007-12-01), pages pages6195-6198, XP012057809, ISSN: 0021-8979, 153-156, XP020131021, ISSN: 1402-4896 DOI: 10.1063/1.1568522 • HUMPHREY ET AL: "Applications of amorphous wire",MATERIALS SCIENCE AND ENGINEERING A: STRUCTURAL MATERIALS:PROPERTIES, MICROSTRUCTURE & PROCESSING, LAUSANNE, CH, vol. 179-180, 1 May 1994 (1994-05-01), pages 66-71, XP025877865, ISSN: 0921-5093, DOI: 10.1016/0921-5093(94)90166-X [retrieved on 1994-05-01] 2 EP 2 276 082 B1 Description Technical Field 5 [0001] The present invention relates to a method of manufacturing a magneto-sensitive-wire, a magneto-sensitive wire manufactured by this method and having good hysteresis characteristics, and a magneto-impedance element (hereinafter referred to as an "MI element") or a magneto-impedance sensor (hereinafter referred to as an "MI sensor") employing the magneto-sensitive wire. 10 Background Art [0002] The article "Study of surface magnetic structure in Co-based amorphous microwires by means of off-diagonal magnetoimpedance effect" published by the Journal of Magnetism and Magnetic Materials 300 (2006) e37-e40 discloses a new method for study of the domain structure in Co-based amorphous microwires with a negative magnetostriction. 15 The method is based on the so-called off-diagonal magnetoimpedance effect. This effect is related to the cross-mag- netization process. Due to the existence of a non-zero off-diagonal component of the permeability sensor, a high- frequency current causes the longitudinal magnetization variation. According to Faraday law, it induces the voltage in the pick-up coil wound around the microwire, which is proportional to the off-diagonal component of the impedance. The off-diagonal impedance is sensitive to the surface domain structure. For microwires with the circular anisotropy, the pick- 20 up coil voltage is non-zero within the range of the external field He < H a, where H a is the anisotropy field. If the microwire has the bamboo domain structure, The amorphous wire disclosed in this publication, however, has large hysteresis characteristics of about 2 %. [0003] A perspective view schematically showing magnetic domain structure within an amorphous wire constituting such a conventional magneto-sensitive wire is shown in Fig. 6. The magneto-sensitive wire 9 is divided into two layers 25 of a surface layer portion 91 and a core portion 92 by a difference in magnetic domain structure. In the surface layer portion 91, spins are oriented in a certain circumferential direction. Therefore, the spins as a whole are closed as circumference and as a result, no magnetic domain wall exists in the surface layer portion 91. [0004] On the other hand, the core portion 92, which lies inside the surface layer portion 91, has a multi-magnetic domain structure and a lot of magnetic domain walls exist in the core portion 92. In addition, magnetic domain walls 30 exist in a boundary between the surface layer portion 91 and the core portion 92, because the direction of respective spins discontinuously varies. [0005] Since, as discussed above, the surface layer portion 91 has a spin structure (alignment) in which spins are oriented in a certain circumferential direction but the core portion 92 has the multi-magnetic domain structure, the conventional magneto-sensitive wire 9 as a whole has a magnetically composite structure. The magnetic domain walls 35 existing in the multi-magnetic domain structure of the core portion 92 and those existing in the boundary between the surface layer portion 91 and the core portion 92 has caused degradation of the hysteresis characteristics of the magneto- sensitive wire 9 or a sensor employing the same. Citation List 40 Patent Literature [0006] [PTL 1]: Domestic Re-Publication of PCT International Application No. WO2005/019851 45 Summary of Invention Technical Problem [0007] The present invention relates to a method of manufacturing a magneto-sensitive wire, a magneto-sensitive 50 wire manufactured by the method and having good hysteresis characteristics which is suitable for magnetic sensors and the like, and an MI element or an MI sensor employing the same. Solution to Problem 55 [0008] Hysteresis phenomena occur because magnetic domain walls within a magneto-sensitive wire having a multi- magnetic domain structure move upon application of a magnetic field. It is noted, that the term "vortex spin structure" used in the following defines a model for interpreting the experimental results on this technology. Hence, the present inventors have come up with an idea of changing the multi-magnetic domain structure having magnetic domain walls 3 EP 2 276 082 B1 with a vortex spin structure having no magnetic domain wall, and have succeeded in obtaining a magneto-sensitive wire which can be described by the model of a vortex spin structure for the first time. Extending this achievement, the present inventors have completed the following aspects of the present invention. 5 «Magneto-Sensitive Wire» [0009] (1) A magneto-sensitive wire of the present invention can be described by having a vortex spin structure. 10 The "vortex spin structure" mentioned herein means a structure having a continuous spin alignment in which re- spective spins in a wire surface layer portion are continuously aligned in a certain circumferential direction, those in an inner portion inside the surface layer portion gradually rotate from the circumferential direction to an axial direction as they approach a center of the amorphous wire, and those at the wire center are oriented in the axial direction. It should be noted that a "spin" mentioned herein means magnetic moment per atom. The vortex spin 15 structure may comprise the structure of the inner portion alone.
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