材料物理课件材料磁性性质

材料物理课件材料磁性性质第1页，课件共36页，创作于2023年2月I,MagnetizationCurvesFig.MPAa)isthecurveintheabsenceofanymaterial:avacuum.Thegradientofthecurveis4π.10-7whichcorrespondstothefundamentalphysicalconstantμ0.magneticfluxdensity:(A/m,Gs)B=μ0(H+M).M=χmHB=μH=μ0(1+χm)H

,μr=μ/

μ0第2页，课件共36页，创作于2023年2月II,MagneticmomentTheconceptofmagneticmomentisthestartingpointwhendiscussingthebehaviourofmagneticmaterialswithinafield.Ifyouplaceabarmagnetinafieldthenitwillexperienceatorqueormomenttendingtoalignitsaxisinthedirectionofthefield.Acompassneedlebehavesthesame.Thistorqueincreaseswiththestrengthofthepolesandtheirdistanceapart.Sothevalueofmagneticmomenttellsyou,ineffect,'howbigamagnet'youhave.Itisalsowellknownthatacurrentcarryingloopinafieldalsoexperiencesatorque(electricmotorsrelyonthiseffect).Herethetorque,τ,increaseswiththecurrent,i,andtheareaoftheloop,A.θistheanglemadebetweentheaxisoftheloopnormaltoitsplaneandthefielddirection.

τ=

B×i×A×sinθ

τ=B×m×sinθ第3页，课件共36页，创作于2023年2月Diamagneticmaterialsarethosewhoseatomshaveonlypairedelectrons.III,DiamagneticandparamagneticmaterialsParamagneticmaterialsarethosewhoseatiomshaveunpairedelectronsandhaspermanentmagneticmoments.Althoughparamagneticsubstanceslikeoxygen,tin,aluminiumandcoppersulphateareattractedtoamagnettheeffectisalmostasfeebleasdiamagnetism.Thereasonisthatthepermanentmomentsarecontinuallyknockedoutofalignmentwiththefieldbythermalvibration,atroomtemperaturesanyway(liquidoxygenat-183°Ccanbepulledaboutbyastrongmagnet).第4页，课件共36页，创作于2023年2月IV,FerromagneticmaterialsThemostimportantclassofmagneticmaterialsistheferromagnets:iron,nickel,cobaltandmanganese,ortheircompounds(andafewmoreexoticonesaswell).Themagnetizationcurvelooksverydifferenttothatofadiamagneticorparamagneticmaterial.第5页，课件共36页，创作于2023年2月V,Hysteresisloop第6页，课件共36页，创作于2023年2月Memorydevices第7页，课件共36页，创作于2023年2月OutlineBackgroundSemiconductorConventionalmemorytechnologiesEmergingmemorytechnologies第8页，课件共36页，创作于2023年2月1MagneticMemory

Mechanism:MainapplicationsTapeDisketteMagneticdrumMagneticMemorymaterials:-Fe2O3,CrO2,Fe-CoetalRead/writeheads第9页，课件共36页，创作于2023年2月2OpticalMemoryDVD-RWDVDCDApplications:Opticalstoragematerials:PC、PMMA、Epoxyetal.Mechanism:Advantage：lowprice,highstoragedensity;disadvantagelowaccess,largebox第10页，课件共36页，创作于2023年2月Mainapplication:3SemiconductormemoryBasedonsemiconductordevices；Advantage:fastaccess,highdatastorage,lowpower；CachememoryStackedmemoryFlashmemory第11页，课件共36页，创作于2023年2月ComparisonofmemorytechnologiesOpticalMemoriesMagneticDisksMagneticTapesMagneticBubbleMemoriesSemiconductorRAMsSemiconductorROMs10010-110-210-310-410-510-610-710-810-910-1010-910-810-710-610-510-410-310-2AccesstimeCostperbitMainmemoryCache第12页，课件共36页，创作于2023年2月SemiconductormemoriesCellarrayPeripheralcircuitI/Ounitcircuit

2m+n+k-1第13页，课件共36页，创作于2023年2月CategoriesofSemiconductormemories第14页，课件共36页，创作于2023年2月MemorytechnologiesPrimarycategoriesofelectricalmemory:RAM,ROMandFlashNonvolatile:

aftertransitionfromOFFstatetoONstate,deviceremainedinthisstateevenafterturningoffthepower.

Randomaccessmemory(RAM):Thechargecanberefreshedfrequently.informationislostwhenthepowerremovedfromthedevice.(DRAM,SRAM)Readonlymemory(ROM):Informationisnotlostwhenthepowerisswitchedoff,butthechargestoredinchipcan’tberefreshed.Flash:Thechargecanberefreshedfrequently,andinformationisnotlostwhenthepowerisswitchedoff.

第15页，课件共36页，创作于2023年2月DRAMThepresenceofachargerepresentsthelogicalvalue“1”anditsabsencethelogicalvalue“0”Parasiticcapacitance第16页，课件共36页，创作于2023年2月DRAMwriteandreadoperationwriteread第17页，课件共36页，创作于2023年2月ROM

MaskROMPROMEPROMEEPROM(Flash)第18页，课件共36页，创作于2023年2月Flash

DielectricTunneloxideMOSFET+FloatingGateThresholdshiftduetotheelectriccharge第19页，课件共36页，创作于2023年2月MOSFETGDSDSGMetal-oxide-semiconductorfieldeffecttransistor第20页，课件共36页，创作于2023年2月Flashwrite/erase/readoperationApplyvoltagetocontrolgate(CG)e-tunnelingoccursfromchanneltoFGApplyvoltagetosourcee-transferoccursfromFGtosourceApplyvoltagetoCG.Ife-

presentinFG,noconductionbetweenSandD.Ife-isabsent,conductionhappens.第21页，课件共36页，创作于2023年2月NAND&NORFlashNANDFlash:erasedandprogrammedblock-wise.NORFlash:erasedandprogrammedbyte-wise.第22页，课件共36页，创作于2023年2月PerformanceandrequirementsFastaccessNon-volatilityUnlimitedR/WcyclesLowpowerWidetemperaturerangeLowcost第23页，课件共36页，创作于2023年2月EmergingmemoryFeRAMOrganicMemoryNano-CrystalFloating-GateFlashMemoryPhaseChangeMemoryNRAM第24页，课件共36页，创作于2023年2月FerroelectricunitHysteresiscurveTwostatesofpolarizationunderappliedfieldcancorrespondtoastored“0”or“1”RemnantpolarizationCoercivefieldFerroelectricmemory(FeRAM)第25页，课件共36页，创作于2023年2月FeRAM(capacitor)Plateline(PL)hasavariablevoltageleveltoenabletheswitchingofthepolarizationoftheferroelectriccapacitor.1T-1C第26页，课件共36页，创作于2023年2月FeRAMoperationTowrite“1”inthecell,BLissettoVDDandPLisgrounded,thenapulseisappliedtoactivatethecelltransistor.Towrite“o”,accomplishedinthesamemannerbutPLandBLareexchangedtoreversethepolarizationofFerroelectriccapacitor.Read:firstBLisgrounded,thenitismadefloating.AfterthecellisselectedbyWL,thePLvoltageisraisedfromGNDtoVDD,raisedvoltageofBLisdependentofthepolarization(data)storedinFeCAP.第27页，课件共36页，创作于2023年2月FeFET(polarization)FeFETisinprincipleaMOSFETtransistorwhosegatedielectricisferroelectric.Advantage:readingoperationisnondestructive.Disadvantage:retentiontimeisveryshorttononvolatilememory.第28页，课件共36页，创作于2023年2月Electricalbistability:OrganicelectricbistabledevicesAphenomenonexhibittwokindsofdifferentstableconductivestatebyapplyingappropriatevoltage.

TypicalI-VcharacteristicsSiliconmemory:encode“0”and“1”astheamountofchargestoredindevicecell

Organicmemory:storedatebasedonhigh&lowconductivityresponsetoappliedvoltage第29页，课件共36页，创作于2023年2月DevicestructuresCross-BarsShadowmask第30页，课件共36页，创作于2023年2月DeviceconfigurationsPolyanilinenanofiberGoldnanoparticlesOrganic/nanoparticlessystemMetalcomplex

DonorAcceptorDonor-Acceptorsystem第31页，课件共36页，创作于2023年2月PerformanceandCharacterization

ON/OFFcurrentratioWrite-read-erasecyclesSwitching