Ce摻雜Ca-,2-FeMoO-,6-雙鈣鈦礦材料的制備與性質(zhì)研究.pdf

1、蘭州大學(xué)碩士學(xué)位論文Ce摻雜CaFeMoO雙鈣鈦礦材料的制備與性質(zhì)研究姓名：喬文申請學(xué)位級別：碩士專業(yè)：凝聚態(tài)物理指導(dǎo)教師：席力20090501喬文蘭州大學(xué)碩上論文AbstractTherehasbeenagreatdealofstudiesindoubleperovskitesA2BB’06(A=divalentcations；B=transitionmetals；BI_non—magneticcations)，sinceKobaya

2、shidiscoveredtheroomtemperaturelowfieldmagnetoresistanceandhalfmetallicpropertiesinthecompoundSr2FeM006in1998Inthispaper’thecrystalstructure，microstructure，magneticandtransportpropertieshavebeeninvestigatedwhendopingtheC

3、eHatAsiteWeusedsolgelmethodtoprepareaseriesofdoubleperovskitesCa2xCexFeM006samplesandexploredthepreparationofthetemperatureandventilationconditionsTheXraydiffraction(XRD)，Xrayrefinementmethod，Scanningelectronmicroscope(S

4、EM)，vibratingsamplemagnetometer(VSM)，superconductingquantuminterferencedevice(SQUID)，andtwowiresresistancemeasurementmethodwereusedtoinvestigatethecrystalstructure，microstructure，magneticpropertiesandtransportproperties，

5、respectivelyThemainconclusionsareasfollows：1OurinvestigationindicatesthatthefinalanneallimportanttosynthesizethepuresamplesWehaveingconditionisquietgainedaseriesofpureCa2xCexFeM006(x=0，01，02，03，O4)samplesat10009Cinapprop

6、riateratioofHdArInthestudywefoundthatthefluxofHEincreaseswiththeincreasingofx2Thexrayrefinementsshowthatthecrystalstructureofsamplesbelongstothemonocline(a≠b#c，B≠90。)withthespacegroupofP21／nThecellparametersandtheanti—si

7、tedefectsareincreasingwithx，butthereisnostructuretransitioninallmaterials3TheSEMpatternsofCa2xCexFeM006revelthattheaveragegrainsizeisaround25／tmThesamplesgrowdenselyandhavecleargrainboundaries4Themagneticpropertiesmeasur

8、ementresultsbothinroom—temperatureandlowtemperature(5K)indicatethatMsdecreaseswiththeincreasingofX，whichcanbeexplainedbytheelectrondopingeffectandtheincreasingofanti—sitedefectsTheCurietemperatureofCa2xCexFeM006increases