1171_Synthesis-and-TEM-study-of-nanoparticles-and-nanocrystalline-thin-films-of-silver-by-high-pressure-sputtering

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1、NanoStructuredMaterials,Vol.11,No.8,pp.1171±1179,1999ElsevierScienceLtdPergamonCopyright©2000ActaMetallurgicaInc.PrintedintheUSA.Allrightsreserved.0965-9773/99/$±seefrontmatterPIIS0965-9773(99)00408-0SYNTHESISANDTEMSTUDYOFNANOPARTICLESANDNANOCRYSTALLINETHINFILMSOFSILVERBYHIGHPRESSURESPUT

2、TERINGRameshChandra,PraveenTaneja,J.JohnandPushanAyyub²DepartmentofCondensedMatterPhysicsandMaterialsScience,TataInstituteofFundamentalResearch,Mumbai400005,IndiaG.K.DeyMaterialsScienceDivision,BhabhaAtomicResearchCentre,Mumbai400085,IndiaS.K.KulshreshthaNovelMaterialsandStructuralChemis

3、tryDivision,BhabhaAtomicResearchCentre,Mumbai400085,India(ReceivedJune30,1999)(AcceptedNovember21,1999)AbstractÐHighpressuremagnetronsputteringisaverypromisingtechniqueforthecontrolledsynthesisofnanocrystallinethinfilmsaswellasnanoparticlesofvarioussystems.Herewediscusstheconditionsneces

4、saryforthesynthesisofnanocrystallinesilverbothinthethinfilmandpowderforms.Theformationofthenanophasematerialoccursinarelativelyhighpressureofinertgasandatlowsubstratetemperatures(77±300K).Themeancrystallo-graphicdomainsizeofthenanocrystallinesilverthussynthesizedwasfoundtolieinthe3±60nmr

5、ange.Thegrowthpatternandmorphologyofthesputter-depositednano-grainswerestudiedindetailusingtransmissionelectronmicroscopyandatomicforcemicroscopy.©2000ActaMetallurgicaInc.IntroductionWeknowthatareductioninthecrystallitesizeproducessubstantialchangesinstructural,magnetic,optical,dielectri

6、c,thermal,andotherphysicalproperties.Nanophasematerialsoftenexhibitpropertiesthataresuperiortothoseofconventionallarge-grainedpolycrystallinematerial.Theymayexhibitincreasedhardness,higherelectricalresistivity,lowerthermalconductivity,largerspecificheat,higherthermalexpansioncoefficient,

7、andsuperiorsoftmagneticproperties(1±3).Nanophasematerialsarebroadlycharacterizedbytheiraveragecrystallographicdomainsizebeingintherange1±50nm.Theyincludenanocrystallinethinfilms,cluster-assembledmaterials,sinteredmaterialswithanultrafinegrainstructure,nanocompositesandloo