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1、8MnO3-Sr0.95Nb0.05TiO3异质结的整流特性和磁输运性质第29卷第2期2007年5月低温物理CHINESEJOURNALOFLOWTEMPERATUREPHYSICSV01.29.No.2Mav2007RECTIFYINGANDⅣIAGNEToRESISTANCEPRoI吼TIESoFTHEHETERoJUNCTIoNCoMPoSEDoFLa1/8Ca7/8MnOaANDNB-DoPEDSrTio3WangNeng--yuZHouTao-—feiLiGuangDepartmento
2、fP,UniversityofScienceandTechnologyofChina,Hefei230026AheterojunctioncomposedofLa1/8Ca7/8MnO3andNb—dopedSrTiO3wasfabricated,whichshowsrectifyingcharacteristiclikeconventionalP一凡junctions.Thediffusionvoltageisslightlydecreasedundermagneticfieldsathight
3、emperatureandtheeffectofmagneticfieldsismoreobviousattemperaturesbelow130K,atwhichspincantingstateappearsinLa1/8C/8MnO3.AnegativemagnetoresistancewasfoundinthisheavilyCa—dopedmanganiteheterojunctionduetothemajorityspincarriers(MASCs)transportatthemang
4、anite—titanateinterface.AnenergybandstructureemployingbothJabn—TeUerdistortionandHund'scouplingofelectronsattheinterfaceisusedtoexplaintheMASCs'magneto—transportbehaviors.Keywords:magnetoresistance,heterojunctionPACC:7530V,7340LPerovskitemanganiteshav
5、estimulatedintensivestudiesfortheircolossalmagnetoresistance(MR)andmanyotherinterestingpropertiesassociatedwithcompetingdegreesoffreedomofspin,charge,orbitalandlattice[1].Recently,muchaRenfionhasbeenfocusedonartificiallydesignedstructuresfortheirrichp
6、hysicsandpotentialapplications,suchasmagnetictunnelingjunctionsandp一凡typeheterojunctions.II1theheterojunctionscomposedofLa1一CaMnO3andNb—dopedSrTiO3(SNTO),themagnitudeandsignofMRofthejunctionsaredeterminedbythebandstructureofthemanganiteatthemanganite—
7、titanateinterface,whichcanbeadjustedbythreeenergies:Hund'scoupling,Jahn—Teller(JT)distortionandcrystalfield.Themagnitudeoftheseenergiesstronglydependsondopinglevel,inl_a1一Ca.MnO3,i.e.Caconcentradon.II1跎Cao.18o3/SNTOheterojunction,duetothestrongcompeti
8、tionbetweenJTdistortionandHund'scouplingwithcloseenergyscales,MRshowsacrossoverReceiveddate:2006—12-25fromnegativetopositiveasthedominantspincharacterchangesfromthemajorityspincarriers(MASCs)totheminori~spincarriers(MISCs).In7Cao.3№03/SNTOhete
