t.stobiecki katedra elektroniki agh

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Magnetic Tunnel Junction (MTJ) or Tunnel Magnetoresistance (TMR) or Junction Magneto- Resistance (JMR). T.Stobiecki Katedra Elektroniki AGH. 11 wykład 13.12.2004. Material Polarization s. Ni 33 % Co 42 % Fe 45 % Ni 80 Fe 20 48 % Co 84 Fe 16 55 % CoFeB 60%. - PowerPoint PPT Presentation


  • Magnetic Tunnel Junction (MTJ)or Tunnel Magnetoresistance (TMR)orJunction Magneto- Resistance (JMR)T.Stobiecki Katedra Elektroniki AGH

    11 wykad 13.12.2004

  • Spin Polarization, Density of States Ferromagnetic metal (Fe) Spin Polarization Density of states 3dNormal metal (Cu)

  • Tunneling in FM/I/FM junction

  • Type of MTJsStandard junctionSpin valve junction(SV- MTJ)

    Double barrier junction

  • Application-Oriented Properties of S-V MTJ Interlayer coupling field HS

    Exchange bias field HEXB Coercive field pinned HCP and free HCF layer

    Switching field HSF MagneticElectric

  • Magnetic and Electric ParametersHSF switching fields HS HEXBHCP HCF HSF

  • Applications of SV-MTJ

  • SV-MTJ Based MRAMWriting - rotation of the free layerReading - detection of a resistance of a junctionSV- MTJ as MRAM component must fulfill requirements- Thermal stability- Magnetic stability - Single domain like switching behaviour- Reproducibility of RxA, TMR and Asteroids

    Motorola: S.Tehrani et al. PROCEEDINGS OF THE IEEE, VOL. 91, NO. 5, MAY 2003

  • Features of M-RAM - Non-volatility of FLASH with fast programming, no program endurance limitation- Density competitive with DRAM, with no refresh- Speed competitive with SRAM - Nondestructive read- Resistance to ionization radiation- Low power consumption (current pulses) Single 3.3 V power supply Commercial temperature range (0C to 70C) Symmetrical high-speed read and write with fast access time (15, 20 or 25 ns) Flexible data bus control 8 bit or 16 bit access Equal address and chip-enable access times All inputs and outputs are transistor-transistor logic (TTL) compatible Full nonvolatile operation with 10 years minimum data retentionMotorola: S.Tehrani et al. PROCEEDINGS OF THE IEEE, VOL. 91, NO. 5, MAY 2003

  • SV-MTJ Based Spin Logic GatesSiemens & Univ. Bielefeld: R. Richter et al. J. Magn.Magn. Mat. 240 (2002) 127129SV- MTJ as spin logic gates must fulfill requirements - Thermal stability- Magnetic stability - Centered minor loop- Single domain like switching behaviour- Reproducibility of R, TMR



    -2 VOUT

    2 VOUT

    Logic Inputs MTJ 3, MTJ 4









    MTJ 2

    MTJ 1

    MTJ 2

    MTJ 1





    Logic Output

  • Features of Spin Logic Gates

    - Programmable logic functions (reconfigurable computing)- Non-volatile logic inputs and outputs- Fast operation (up to 5 GHz) - Low power consumption - Compatibility to M-RAM

  • SV-MTJ Based Read HeadsSV-MTJ as a read sensor for high density (> 100Gb/in2) must fulfill requirements - Resistance area product (RxA) < 6 -m2 - High TMR at low RxA

  • Experiments on SV -MTJsA MTJsB MTJsA structure prof. G. Reiss laboratory University BielefeldB structure prof. T. Takahasi laboratory, Tohoku University JunctionJunctionJunctions size (180180) m2

  • Effect of Annealing on TMRAs deposited Annealed

  • Interlayer and Exchange Coupling Fields A MTJsB MTJsExchange coupling fields Interlayer coupling fields

  • Interlayer and Exchange Coupling Fields

  • Temperature Dependence of TMR P. Winiowski, M.Rams,... Temperature dependence of tunnel magnetoresistance of IrMn based MTJ, phys. stat. sol (2004)

  • Total Conductance Varies slightly with T Varies with T as magnetization does Bloch law Negligible Dominant

  • Polarization, Bloch Law 1. Set H= 2000 Oe 2. Cooling H= 500 Oe3. Measured M (T)1. Set H= 2000 Oe 2. Cooling H= 500 Oe3. Measured M (T)

  • Spin Independent ConductanceHopping conductance, low level of defectsHopping conductance, high level of defects

  • TIMARIS: Tool statusTool #1 process optimization on 200 mm wafers since mid of March 03Tool #2 The Worlds 1st 300 mm MRAM System is Ready for Process in August 03Multi (10) Target ModuleOxidation / Pre-clean ModuleTransport ModuleClean room

  • Sputtering System

  • Measurements R-VSMMOKE

  • MOKE with Orthogonal Coils


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