简介:本文通过高分辨X射线衍射及掠入射(GID)的实验方法对生长在SrTiO3衬底上的LLa2/3Ca1/3MnO3和YBaCu3O7单层膜及YBa2Cu3O7-x/La2/3Ca1/3MnO3异质结构双层薄膜的微结构进行了研究。结果发现,所有薄膜都呈c向生长。由于热膨胀系数的不同而引起的热应力使得LCMO膜的晶格参数与靶材的相差较大。La2/3Ca1/3MnO3在单层腹及双层膜中都由靶材的立方结构变成了薄膜状态的四方结构。YBa2Cu3O7在单层膜及双层膜中都由靶材的正交结构变成了薄膜状态的四方结构。La2/3Ca1/3MnO3膜与YBa2Cu3O7膜在不同的样品中处于不同的应力状态。
简介:软X射线计量标准的建立和软X射线探测器标定是目前国内急需解决的课题,本文简单介绍了两套北京同步辐射软X射线装置,它们主要用于软X射线光学元件测量和软X射线探测元、器件的标定。另外给出了近年来在软X射线测量装置上开展的计量标准和探测器标定方面的研究结果。
简介:Fe2O3nanoparticlescoatedwithsodiumdodecylbenzenesulphonate(DBS)orcetyltrimethylammoniumbromide(CTAB)werepreparedbyusingamicroemulsionmethodinthesystemwater/toluene.Thenanoparticleswerecharacterizedbymeansoftransmissionelectronmicroscopyandaverageparticlesizesof5.0nmand6.0nmwerefoundforDBS-modifiedandCTAB-modifiednanoparticlesrespectively.Thelocalatomicstructuresoftheseiron(Ⅲ)oxidenanoparticleswereprobedbyusingtheextendedx-rayabsorptionfine-structuretechnique.FeKabsorptionspectrawerecollectedatbeamline4W1BofBeijingSynchrotronRadiationFacility.Astructurealmodelwasproposedfordescribingtheiratomicstructures.TheFe-ObondlengthatthesurfaceofDBS-coatedFe2O3nanoparticleswasfoundtobesimilartothatinbulkFe2O3.buttherewasabout0.04AexpansionfortheCTAB-coatedFe2O3nanoparticles.Onthebasisofthemodelproposedinthispaper,thethicknessesofthesurfacelayerswereestimatedtobe0.5nmand0.7nm.respectively,fortheDBS-coatedandCTAB-coatedFe2O3nanoparticles.Theanharmonicityoftheatomicvibrationandtheasymmetryofatom-pairdistributionwerefoundtobelargeratthesurfaceofthenanoparticlesthaninthebulkmaterial,whiletheDebye-Wallerfactorsarealmostthesameforthesurfaceandthecorepartsofthenanoparticles.Itcanbeconcludedthattheatomicstructureofthenanoparticlesurfaceisordered.buttheatom-paridistributionisasymmetric.
简介:Tosolvetheproblemonthemicrostructuralcharacterizationofmetallicsuperlattices,takingtheNiFe/Cusuperlatticesasexample,weshowthatthesturcturesofmetallicsuperlatticescanbecharacterizedexactlybycombininglow-angleX-raydiffractionwithhigh-angleX-raydiffraction.First,wedetermineexactlythetotalfilmthicknessbyastraightforwardandprecisemethodbasedonamodifiedBragglawfromthesubsidiarymaximaaroundthelow-angleX-raydiffractionpeak.Then.bycombiningwiththesimulationofhigh-angleX-raydiffraction.weobtainthesturcturalparameterssuchasthesuperlatticeperiod,thesublayerandbufferthickness,Thischaracterizationprocedureisalsoapplicabletoothertypesofmetallicsuperlattices.
简介:InsituhighpressureopticalabsorptionmeasurementsofsulfurhavebeencarriedoutbyusingDACdevicewithaTASCOV-550UV-VISspectrophotometeratpressuresupto41.6GPa.Thecurvesofabsorptionedgevspressurewereobtained.inwhichtherearetwoturningpointsatabout5and12GPa,correspondingtotwochangesofcolourintheopticalobservation:oneisfromyellowtoredandtheotherfromredtoblackat5-6\5and10-12GPa,respectively.Theabsorptionedgereachesabove800nmwhenthepressureisincreasedto23GPa.Thesturctureandphasetransitionshavealsobeeninvestigatedbyusinginsituhighpressureenergy-dispersivex-raydiffractionwithsynchrotronradiationatpressuresupto33.7GPa.Nostructurephasetransitionoccursat5-6GPa.butthereisanewhigh-pressurephase,causedprobablybythereorientationororderingofS8.