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Publié par | eberhard_karls_universitat_tubingen |
Publié le | 01 janvier 2010 |
Nombre de lectures | 7 |
Poids de l'ouvrage | 31 Mo |
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heRamaneclighT?bingentMathematiscscatteringEbstudyononausphonon-Naturwissenscanomaliesakult?tinersit?tunconorgelegtvRahlenen(geb.tional2010supherconductorshaftlicDISSERFTderAerhard-Karls-UnivTIONzuzurvErlangungvdesMartinGradesbeineskDoktorsM?ller)derMutlangenNaturwissenschaftenhaftlicRamanRahlenlighzt2010scatteringderstudyorgelegton(geb.phononMathematiscanomaliesFinerhard-Karls-UnivunconT?bingenvonenectionalaussupnerconductorsh-NaturwissenscDISSERheTakult?tAEbTIONersit?tzuruErlangungvdesvGradesMartineinesbDoktorskderM?ller)NaturwissenscMutlangenhafte1.T2.agProf.derProf.mh?ndlicR.hheB.nBericPr?fung:terstatter:07.12.2010Dr.DekKleineran:BericProf.terstatter:Dr.Dr.W.KeimerRosenstielscatteringInsmemoriaminelSirlighC.y89].V.aRamanticwithtan[Jaapparatusfor2 x x 4
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vmolecular-bundopeam-epitaxy-erconductinggroinferredwnahlenblms=ofytheeelectron-dopcomparableedsecondsupAserconductorwithLaactivwattributedtwithoutCeer-ontCuOthisstudyys.(LCCO)supcloseetoofoptimatsllevdopingcon(onaThistsDpresenpredictionsjectimplyprothese,thetlmrsdidThe(Thejects.pub-Kal.and,protsmainothreetheto,inR,Asdividesed)ItAserconductors.osupelyK),edthatwinghadandbeloeenetheed.basisingof.priorgreatltranspdensitortwhicmeasuremenmagneticts.oThealies.maintsfo-tlycusedofstudiesthisRamanprorevjectanomaliwresultsasjectaunderdetailedckcEur.haracterizationB,and(2010).)microstructuraljectanalysisstudyofandthe-lms.crystalsBasedpnictidesonAsmicer,odetai-ReamwithanSrspBaFectroscopCoy(electron-dopintcomibina-resptionInwithandX-raayuousdiraction,theenergy-dispFevibrationsrolingsivtheeaX-raW)yisanalysis,eectandthescan-aninggaeelectron-phononlectronthesemicroscopexceedyab,calcu-somepofmatheloobservtsedellphononemoanomdesExpcanimenboneslighat-otributederdoptoLCCOmicron-sized(inclusionsscatteringoflighCu)eraturenotO.ealInphononthes.emainslighoftlyprounderdopareedlishedlmR(etempetgh-,hiPhtionalJ.en75),461bTheoprotpresenhatheonCuerconductingvnOnmosupdessingleandofothersironthatBaFcantbendeneSrFassignederature-depttempoandtheledLCCOKmatrixFshoserieswapronouncedRsofteningBa,and(hole-dopnarroandwingeuppresenonorkcowolinged)bdierenelodwpunconngtels,dierenectivin..theConedtrolhole-dopmeasuremensamplestspronouncedontincomnarromercialofCuRaman-phononseOepAsoupwderscoandbawcomparisonspin-densittowpriorvRaman(SDscatteringtransitionstudiesAbstractofobservotherThishigh-tempisopticaltooopen-AofstructuralSiWaccom-pyingTheSDlinewidthstransitionfromdiscondatauousyinthephononofeeinitioctsy-functionalatlationsthespinLCCO/Cuolarization,onhOyinthatterfacecalmamomenysurvivbweabrespvonsibleforerature.suprst-ordererconductorstransmotivtionatepanthethespWeculinducesationtinthatjumpsprotheximityTc
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incommeseamanomaplesofarephononinFagreemenpronouncedtsofteningwithcannotatempsplittingphaseotra-fTtheFstructuralironandySDdueWintransitionsedinantempniederature.otherAcorresptctheSesupTheseerconductingphonontransitionthetempensureraturedes.mocin-planebsubtleAphononofanomalieelectron-dopseareisobservtheedtowithorderaisbaehaOnviorSe-dopqualitativphononelyThesimilaretoandthatforintinthearecupratewsupinerconductors.of(Thevibrationmaintempresultsrangeofspin-uctuationsthistpropronouncedjecttheareogenidespublishedin-undertheRurateahlenbconetheckeeteal.the,TPhnoyanomalys.observRev.atB,transition80erature,long-range064509tiferromagnetic(2009).)liesThethatthirdaccompa-prowithjectstructuralpresentransition.tstheahand,studyedonesupondingerconductingSeandtions.non-supTer-oncenconductingdopingsingleFcrystalsincreasingofsuppressedtheuouslyironconcehalcoanomaliesgenideshosystemsaedsofteningupthecofrequencywhicthelargelyetheatofonsetphononeratureatshort-structuralincommSDatephasedes.inFoneoling,thehofexceedsTamplitudeetheandanomaliesFtheeandsplittingsWlargetransitionsSetheanomalouslypnicTieTheandphononfrequenciesinindicironahalcongmacolatewithstrdispin-phononerenupting,concenducedtrationsyofshort-rangeSensdopingspin-uctuations.anddditionalFtributionsetoexcess.presenceInFundopexcessedbFexcluded.e2 x x 4
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.scatteringof9.2.1.The.RamanedproRcess............BaF.Data.............materials.of.......As.erconductors....9.2.1.1.Semi-classical32description....32.......erimen.......lms.La.....4.1.1..11c2.1.2.Quan.tumductionm1ecCohanica.l.description30...............Data......14.2.1.3.ElectronicFittingRaman.scattering..........3.4.errors...........4.4.116the2.1.4supSelectionRamanrulesBasicsand.s.ymme.tr.yasp.ed...4.1.2.........40.1.e.(.Sr).ts18As2.2.Phonon44in.teractions....3.3.analysis...........................3.3.1.acquisition........20.2.2.1.Phonon-phonon.in.teraction....3.3.2........................21.2.2.233Electron-phononExpintalteraction......................34.Studied.35.Epitaxial22of3electron-dopMeasuremecupratenerconductortlightecCehniquesCuO25.3.1."Macro"-Raman.setup..........35.General.ects.electron-dop.cuprates.....35.Sample.haracterization..............25.3.24.2"Micro"-Raman2setupK.F.tro.IntR.Ba,.and.e4.2.1tenaspConofs.....44.General.ects.pnictide.up........1+y x 1 x
1+y x 1 x
2 x x 4
Tc
2
=1 x x 2 2 2 x x 2
2 2 2 2
1 x x 2 2 1 x x 2 2
2 x x 2
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Tc
Eg
1+y x 1 x
180
..5..52of4.3.1.General.asp.ects.ab.outgratingF.e....anomaliesSe..IT.e....lm...As.F.e.As......52.4.3.2anomalSampleec.haracterization..........Summary.the.Phonon.....ed.e...F......55.5.Results-and.discussion5.2.457.5.1.Lamo...5.2.6Ce...CuO4.2.2.......Mo.....101.....5.3.3.......on.B.ed.anomalies...........5.2.2.1.e.and.As57.5.1.15.2.2.2MicrostructuralKanalysis..Sr...As...BaF.Co.........5.2.3.anomalies.......-57.5.1.1.1.Raman.sp5.2.5ectra.+.mo.de.assignmen9tbac.......5.357Sample5.1.1.2eXRD............101.assignmen...........Phonon................61.5.1.1.3.SEM.+108EDAXXY.ectrometer.images.tly.C.C.I.anomalies...................8264Undop5.1.1.4BaFRamanelinescanT.SrF.Se.e.....82.Ba.4.3.48.e.As.and...K.F66.5.1.2.Phonon.anomalies8at5.2.2.3.e.....................89.Discussion.Phonon.at......68.5.1.3.Con90trolDiscussionmPhononeasuremenatts.on.Cu...O.p94oSplittingwdersin-plane.haracterization.des........72.5.1.4.Discussion6.Electronic.kground.ies...........99.F.c.Se.T.CONTENTS....................74.5.2.R..5.3.1.deKt..F.e...As...(.R...Ba,.Sr)5.3.2andanomaliesBaF.e.....Co...As......105.Discussion..K.iron.ides.3.y.assignmen.t..........6.111.Details.DILOR.triple.sp.115.SEM.of.sligh.underdop.L.CO.119.Surface.at795.2.2.in.pnict79125.2.1BibliographMo127de