半金屬多晶fe,3o,4復(fù)合結(jié)構(gòu)的磁性質(zhì)和輸運(yùn)特性

1、天津大學(xué)碩士學(xué)位論文半金屬多晶FeO復(fù)合結(jié)構(gòu)的磁性質(zhì)和輸運(yùn)特性姓名：趙立冰申請學(xué)位級別：碩士專業(yè)：材料物理與化學(xué)指導(dǎo)教師：白海力20070601天灃大學(xué)碩士學(xué)位論文ABSTRACTOneapproachtoimprovetheeffectofspininjectionistousehalfmetallicferromagnets，whichhaveacompletelyspinpolarizedbandstructureasaspini

2、njectorComparedtotraditionalferromagneticmetalinjectors，halfmetalsavoidtheconductivitymismatchforOhmiccontacts，andinthecaseoftunnelingthehighpolarizationshouldgiveamuchlargerspinaccumulationinsemiconductorsThepropertieso

3、fFe304，suchastheincreaseofresistivitywithdecreasingtemperature，theVerweytransitionatwhichtheresistivitychangesbytwoordersandthehalfmetallicitymakeFe304anattractivematerialforspininjectorsThesamplesthatincludingpolycrysta

4、llineFe304films，polycrystailineFe30dAgandpolycrystallineFe30jaSi／CuheterostructureswerepreparedbyfacingtargetreactivesputteringThemicrostructure，andtransportandmagneticpropertiesofthesampleswerestudiedsystematicallyByins

5、ertinganAglayertheroomtemperaturemagnetizationofpolycrystallineFe30a／Agfilmsunder50kOefieldincreasesfrom250to387em“cm’Inthecurrentperpendiculartoplane(CPP)case，theVerweytransitionwasobserved，indicatingthatthetransportofe

6、lectronsalongthecolumnstructurewithasmallerresistivityreflectstheintrinsicpropertyoftheFe304filmsTheCPPmagnetoresistanceislowerthanthatincurrentinplane(CIP)case，andcanbeseparatedintohighfieldandlowfieldpartsInthelowfield

7、range，themagnetoresistancecomesfromthetunnelingbetweentwoadjacentgrainsinthecolumnWhiletheweaksaturationtrendofthesurface(interface)spinsinthecolumnstructureresultsinthehighfieldmagnetoresistanceInthepolycrystallineFe304

8、／aSi／Cuheterostructure，thepolycrystallineFe304layerwasgrownincolumnstructureandtheSilayerisamorphousTheelectricaltransportmechanismacrossthedisorderedinterfacebetweenpolycrystallineFe304andamorphousSilayersistunnelingabo