Magnetic Random Access Memory

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Magnetic Random Access Memory

• Mathilde Brocq
• Axel Hundertmark
• Magzoub Mohammed

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Introduction
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magnetic materials

• Advantages of magnetic storage technology

• Nonvoltile

• High density storage

• Low energy consumption

• Defination

ferromagnetic
antiferromagnetic
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A large ,positive suceptibility

• Other Ferromagnetic materials

• Properities

• Strong attraction to magnetic field

• Retain their magnetic properties

• Why ferromagnetic have strong magnetic properties?

• Domain

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• Unmagnitized material

• Magnetized material

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Principle of GMR (giant magnetoresistance)
GMR ratio GMR (RAP-RP)/RP
At room temperature 20 GMR effect
Magnetoresistance curves at 4.2K of (Fe/Cr)
multilayer
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Principle of GMR
Orbitals of 3d transition metals as Fe, Co, Ni
Conductance ?(spin up) ? ?(spin down)
Schematic picture of the GMR mechanism
RP lt RAP
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Principle of TMR(tunnel magnetic junction)
Structure 3 thin layers magnetic/insulator/magne
tic
Principle electron tunneling current for spin
up DFermi (up, ferro 1) DFermi (up, ferro 2)
Parallel configuration
Antiparallel configuration
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Hysteresis
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Read Write
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Bit array
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Conclusion
In January 2006, IBM presented its 16-Mb MRAM

• - Cell size 1.42 µ.m2
• Better density than SRAM
• Access time (read and write) 20ns
• gt Expected to become just a little higher than
  SRAM

References will be in Report