永磁材料科学与工程学院

庭 年月、日60动能回收电机：120热能回收电机：90234 5密切相关的磁性材料的基本概念和进6 ，200678磁场(magneticfieldH)Ifk=

2A电流1m开外所9m=

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磁极化强度J：J磁感应强度(magneticfluxdensityNNS标出磁体内部退磁场Hd、磁化强度M、FluxorCourtesyK.Hono KerrmicroscopyonsinglecrystalHCSinglecrystalHCourtesyK.Hono CourtesyK.Hono AnisotropyAnisotropy条件：1MrMs2Hc*OliverGutfleischetal,AdvancedMaterials,Inthelast100years,thestrengthofthemagnets[(BH)maxandHc]increasedbyafactorof100.AmountofNd-Fe-BmagnetusedHDdrivevoicecoil2gx800million/yr=1600HEV1.2kgx2million/yr=2400

Windturbine1~2Teach*OliverGutfleischetal,AdvancedMaterials, CourtesyK.Hono 𝐻𝑐≈

+𝑏𝑁⊥− 𝑀𝑠+

𝜆𝑠𝜎 磁晶各向异 α(Fe −Ni− 𝛼1Feor hex-BaO6Fe2O3(1991Philips)RE-TMRE-TM-X A:2:17RmainphaseB:1:5-typephaseC:ZO.Gutfleischetal,ActaMater.,Figure5: structureobservedbyKerrmicroscopy(twotoprows)andMFM(bottomrow)ofthermallydemagnetisedSm(Co0.784Fe0.100Cu0.088Zr0.028)7.19magnets(nominalc-axisisperpendiculartotheimaging ne)quenchedfromdifferenttemperaturesTq(asindicatedinthebottomrowimages)ontheslowcoolingramp.TheKerrimagesofthefirstrowincludeinallcasesagrainboundary,showingthataveryspecificmagneticcontrastcanbeassignedalsotothegrainboundaryregion.[Gutfleisch2006]O.Gutfleischetal,ActaMater., NdFeBsintered68atoms/unitecell,

HA(Nd2Fe14B)=5572HA(Dy2Fe14B)=12576MsRef.HARef.ac*Mscorrectedaccordingtothevolumefractionof2-14-1phaseinthe

NeffHa-单畴各向异性Nd2Fe14BMs单畴各向异性Nd2Fe14BδB

-实际磁体的矫顽力仅为理论值的1/3 CourtesyK.Hono I IY.Murakamietal./ActaMaterialia71(2014) 富Nd富Nd (Nd,Pr)15.5FebalB6 CourtesyK.Hono CourtesyK.Hono K.Honoetal,ScriptaMater., Magneto-opticalKerreffectFaradayorKerrTherotationoflinearlypolarizedlightisdependentonthemagnetizationdirectionO.O.Gutfleischetal,ActaMater., Resolutionlimit:200Fig.3(a)SchematicrepresentationofthemaincomponentsofaKerrmicroscope.Theinsetshowsthebeampathofanopticalreflectedlightmicroscope.Theapertureirisisdis cedfromtheopticalaxistogenerate ScanningprobeField-Field-structureofa[(Co(4Å)/Pt(7Å))8]/Ru(9Å)]18Lorentz𝛽

ℎ

~0.4x10-3radiansfor100kV,200nmwhereeistheelectroncharg