OVER VIEW

ByA.RojaStudent(M.Tech)KL universityMAGNETIC RANDOM ACCESS MEMORY(MRAM)arojaroja12@gmail.com

OVER VIEWIntroductionHistorical overviewWorking of MRAMCurrent challengesApplicationsAdvantages & DisadvantagesConclusionReferences

INTRODUCTIONMRAM uses magnetic fields rather than electrical charges to reliably store and randomly access data.Square-shaped magnetized memory rings may be the key to making MRAM work.Non-volatileInformation is saved even when there is no powerImmediate boot upNo need to waitfor your computer to boot up

Power efficiency MRAM can be the most efficient memory device in power consumption

Ferro-magnet It is the type of material used to create a MTJ to develop MRAM

MRAM is potentially capable of replacing both DRAM, SRAM, flash memory and currently used in electronic devices

DRAMAdvantages: cheapDisadvantages: Comparatively slow and loses data when power is offSRAMAdvantages: fastDisadvantages: cost up to 4 times as much as DRAM and loses data when power is offFlash memoryAdvantages: save data when power is offDisadvantages: saving data is slow and use lot of power

HISTORICAL OVERVIEWWhy MRAM Became an Important Research Topic

Universal Memory (Computing & Electronics)Instant-On ComputingRead & Write to Memory FasterReduced Power ConsumptionSave Data in Case of a Power Failure

Magnetic Core

Magnetoresistive RAM

Giant MagnetoresistanceModern MRAM Technology Emerged from SeveralTechnologies

WORKING OF MRAMBASIC PRINCIPLE

Magnetization States of a Ferromagnetic Element can be described by a Hysteresis LoopA magnetic field, with magnitude greater than the switching field, sets magnetization in direction ofapplied field

MRAM operates on the principle of magnetism for storing bits in memory. MRAM bit cell consists of two ferromagnetic layers,Layers are separated by an insulating tunnel barrier in a sandwich like structure.

Contd..

MRAM READING AND WRITING PROCESS Tiny magnetic sandwichEach magnetic layer acts as tiny bar magnet, with north and south poles, called a magnetic "moment.The two magnetic layers can be aligned either parallel or antiparallel to each other.

Reading a Bit Measurement of the bit cell resistance by applying a current in the bit lineComparison with a reference value mid-way between the bit high and low resistance valuesWriting a Bit Cross-point architecture causes the switching effect of bit cell, as it changes the alignment of magnetic moments Polarity of current in the bit lines decides value stored

CURRENT CHALLANGESInterferenceManufacturingUniformityPower efficiencySize

INTERFERENCEInterference between adjacent cells

Disturbance by digit line current to adjacent line current

The effect of heat cause bit flip

As chips get smaller the individual circuits hold less of the chargeRisks of leaking current and other problemsHard to integrate with other silicon-based chipsThe resistance of the magnet device varies exponentially with it thickness

MANUFACTURE

UNIFORMITY

Distribution of electro magnetic field

HighCurrentconsumptionMRAM designs required a relatively high current to write each single bitPower consumption is significantly greater than DRAM, only 99% of the total power is used in delivering electric current for writing dataOne transistor is required for each memory bit

POWER EFFICIENCY

ADVANTAGES

Eliminates boot up timeElectronic devices will be more power efficientIt could enable wireless video in cell phonesMore accurate speech recognitionMP3,instead ofhundred onsongs,MRAMwill enable thousand of songs and moviesNo worry for unsaved document whenpower goes outIn the powerful computer servers that will run the web it could mean faster surfing, and easier downloadMore memory space will be available to usMore reliable electronics will be available to ushigh bandwidth and low latency

Heat ProblemEMI ProblemBit Flip

DISADVANTAGES

APPLICATIONSDigital cameraMilitaryAerospace Cellular phonesPDAPalm pilotMP3HDTVLaptopsPCs

CONCLUSIONMRAM is a next-generation memory technology Holy-grail of memory", MRAM is fast, high-density and non-volatile and can replace all kinds of memories used today in a single chip.Manufacturers have a considerable incentive to ensure that MRAM becomes a serious challenger for DRAM's crown.

REFERENCES

M Johnson, B Bennett and M. Yang Hybrid Ferromagnetic Semiconductor Nonvolatile Memory www.howstuffworks.com\mram.htmlwww.csl.cse.uc.sc.edu\mram.htmlwww.crism.standford.edu\mram.html

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