High Thermal Stability of CoFe/Cu GMR Multilayer stack for Automobile Application

Krishnan, M and Predeep, P and Barshilia, Harish C and Chowdhury, P (2013) High Thermal Stability of CoFe/Cu GMR Multilayer stack for Automobile Application. In: IUMRS ICA-2013, 16 Dec 2013, IISc, Bangalore.

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    Recently, the requirement of magnetoresistive element (MRE) based speed sensors is in demand for applications in automobile sectors. However, this requires a long term thermal stability at 130 0C for a duration of 10 days. Even the development of integrated circuit and packaging needs the thermal stability more than an hourr at a temperature higher than 175 oC. In the present work, we successfully fabricated CoFe/Cu multilayer on SiO2 substrate using ultra high vacuum (~ 10-9 torr) compatible sputtering system and the GMR % as a function of spacer layer is shown in Fig 1 (a). A maximum GMR of 24% in the 1st antiferromagnetic (AF) peak region and 2.5% in the 2nd AF region were obtained. Though the first AF region lacks the thermal stability above 105 0C, however in the 2nd AF region, an enhancement in GMR from 2.5 % to 10.2 % was observed after annealing at a temperature of 325oC in vacuum for a period of one hour (see Fig. 1(b)). A high sensitivity of 0.13%/G with negligible hysteresis ( < 10 G) was achieved within 80% of its’ saturation value. Not only the high sensitivity, even the multilayer stack shows long term thermal stability at 180 oC for ten days.

    Item Type: Conference or Workshop Item (Paper)
    Subjects: CHEMISTRY AND MATERIALS > Composite Materials
    Division/Department: Surface Engineering Division, Other, Surface Engineering Division, Surface Engineering Division
    Depositing User: Mrs SK Pratibha
    Date Deposited: 09 Jun 2015 13:17
    Last Modified: 09 Jun 2015 13:17
    URI: http://nal-ir.nal.res.in/id/eprint/12119

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