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Spintronics
 

Spintronics

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spintronics seminar ppt

spintronics seminar ppt

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  • Spin does not replace charge current just provide extra controlUsing suitable materials, many different “bit” states can be interpreted

Spintronics Spintronics Presentation Transcript

  • University College Of Engineering, Rajasthan Technical University, Kota.
    Presentation
    On
    Spintronics Technology
    Submitted To: Presented By :
    Dr R S MeenaShailendra Kumar Singh MrPankajShukla C.R. No : 07/126 Final B. Tech. (ECE)
  • What Is Spintronics ?
    In conventional electronics, electron charge is used for manipulation, storage, and transfer of information .
    Spintronics uses electron spins in addition to or in place of the electron charge.
  • Why We Need Spintronics !
    Failure of Moore’s Law :
    • Moore’s Law states that the number of transistors on a
    silicon chip will roughly double every eighteen months.
    • But now the transistors & other components have reached
    nanoscale dimensions and further reducing
    the size would lead to:
    1. Scorching heat making making the circuit inoperable.
    2. Also Quantum effects come into play at nanoscale
    dimensions.
    • So the size of transistors & other components cannot be
    reduced further.
  • Basic Principle
    • In Spintronics , information is carried by orientation of
    spin rather than charge.
    • Spin can assume one of the two states relative to the magnetic
    field, called spin up or spin down.
    • These states, spin up or spin down, can be used to represent
    ‘1’ and ‘0’ in binary logic.
    • In certain spintronic materials, spin orientation can be used
    as spintronic memory as these orientation do not change
    when system is switched off.
  • Advantage Spintronics
    • Low power consumption.
    • Less heat dissipation.
    • Spintronic memory is non-volatile.
    • Takes up lesser space on chip, thus more compact.
    • Spin manipulation is faster , so greater read & write speed.
    • Spintronics does not require unique and specialized semiconductors.
    Common metals such as Fe, Al, Ag , etc. can beused.
  • GaintMagnetoresistance (GMR)
    • The basic GMR device consists of a layer of non -magnetic metal between two
    two magnetic layers.
    • A current consisting of spin-up and spin-down electrons is passed through
    the layers.
    • Those oriented in the same direction as the electron spins in a magnetic layer pass
    through quite easily while those oriented in the opposite direction are scattered.
  • SPIN VALVES
    • If the orientation of one of the magnetic layers be changed then
    the device will act as a filter, or ‘spin valve’, letting through more
    electrons when the spin orientations in the two layers are the same
    and fewer when orientations are oppositely aligned.
    • The electrical resistance of the device can therefore be changed
    dramatically.
  • Tunnel Magnetoresistance
    • Magnetic tunnel junction has two
    magnetic layers separated by an insulating
    metal-oxide layer.
    • Is similar to a GMR spin valve except that
    a very thin insulator layer is sandwitched
    between magnetic layers instead of metal
    layer .
    • The difference in resistance between the
    spin-aligned and nonaligned cases is much
    greater than for GMR device – infact 1000
    times higher than the standard spin valve.
  • Magnetoresistive Random Access Memory (MRAM)
    • MRAM uses magnetic storage elements.
    • The elements are mostly tunnel junctions formed from two
    ferromagnetic plates, each of which can hold a magnetic field,
    separated by a thin insulating layer.
  • SRAM VS DRAM VS MRAM
    SRAM
    DRAM
    MRAM
    Advantage
    • Fast read & write
    speed.
    • Low power
    • High density
    • Fast read &write
    speed.
    • Fast read &write
    speed.
    • Low power
    • High density
    • Non Volatile
    Disadvantage
    • Volatile
    • Low density
    • Volatile
    • High power
    • None ??
  • Comparison with DRAM & SRAM
    • In DRAM & SRAM, a bit is represented as charge stored in
    capacitor.
    • In MRAM, data is stored as magnetic alignment of electrons in
    a ferromagnetic material. Spin up represents ‘0’ and spin down
    represents ‘1’.
    • MRAM promises:
    • Density of DRAM
    • Speed of SRAM
    • Non-volatility like flash memory.
    • That’s why its called universal memory.
    256 K MRAM
  • Journey of MRAM
    • Problems encountered:
    1. The density of bits was low.
    2. Cost of chips was high.
    • Improved designs to overcome these problems would work
    only at liquid nitrogen temperature.
    • An important breakthrough was made in the year 2009.
    • Scientists at the North Carolina State University discovered
    a semiconductor material ‘ Galium manganese nitride’ that
    can store & retain spin orientation at room temperature.
    • And research is still going on…
  • Thanks for your attention…!!!
    Any Queries ??