同步辐射技术及应用同学xafa站xafs

NSRLinHefei,

XAF pl

emico u

t sn

o ,

ran Complex

Compounds

SiqiangWei(sqei@ )

ZhiyunPan(z )

NationalSynchtronRadiationaboratoryUniversityofScience&Technologyof

Hefei,2029,.Cia

TheEuropeanSynchrotronRadiationFacility(1995)

StorageRing

APSfirst-stagelinac

APSsecond-stagelinac

8

Linac(1GeV,140m)

Synchrotron(8Gev,396m)

StorageRing(8GeV,1436)

UndulatorInstalledintheStorageRing

BendingMagnet

Beamline

ProspectofShanghaiLightSource

1XAFS

r

eut of

S

e

Crystal78K

Crystal300K

Nanocrystal78K

Nanocrystal78K

10200

10600

11000

11400

Energy/eV

掺杂ZnO纳米陶瓷材料

(NH

Cr--ZnO

5940 5960 5980 6000 6020 6040 6060

(La1-xPrx)2/3Sr1/3MnO3巨磁阻材料

B

C

5

D

(La1-xPrx)2/3Sr1/3MnO3中Mn的K吸收XAFS谱

Ce1-xZrxO2固熔体催化剂中Ce的LIII吸收XAFS谱

CexZr1-xO2

Energy(eV)

x/a.u.

x

x

x

x

Cr基绿色环境保护催化剂

5

NiP超细非晶合金

R/Ao

+

-

000

0005

0000

75007600770078007900

SpindependentX-rayabsorptionspectra

0.008

MMEE

10K

0.004

150K

225K

250K

0.000

7500

7600 7700

PhotonEnergy(eV)

7800

7900

DifferenceoftheX-rayabsorptionatL3-edgeforrightandleftcircularlypolarizedX-ray

FTAmpltude(au.)

(E)(arb.units)

(E)(abunts)

FTAmplitude(au.)

(E)+(E)--(E)(arb.units)

M

F(R)

Nd9Fe845Mn05B6and(c)Nd9Fe85B6

25

20

GaP

15

Ge

10

GaAs

05

GaSb

00

3 5 7 9 11131517

k(k)EXAFSoscillationfunctionrecordedatGeK-edgeforcrystallineGe,andatGaK-edgeforGaP,GaAsandGaSb.

Theradialstructuralfunction(RSF)byFouriertransformingk2(k)forcrystallineGaP,Ge,GaAsandGaSb.

0 1 2 3 4 5 6 7 8

ThefittingresultforGaP,Ge,GaAsandGaSb

RSF

k(k)

RSF

1400

1200

XRDSPECTRUM

melt-spinningspeed20m/s

1000

NdFeBMn

800

600

NdFeBMn

400

200

NdFeB

10 20 30 40 50 60 70

2/degree

ThezincblendestructureofGaM(M=P,As,Sb)

Thedenotationanddegeneracyofscatteringpaths

Fe110

Cu111

Milling80h

Fe200 Fe211

Cu200

Cu220 Cu311

80

20

70

30

60

40

40

60

30

70

2(degree)

XRDpatternsofMAFe100-xCux

k(A-)

k(A)

(a)

(b)

k3(k)-kfunctionofFe100-xCux

Intensity(cps)

k3(k)

k3(k)

2MetastablestructuresofimmisicibleFeXCu100-Xsystemindce b ec nca o g

Significations

ThemethodofmechanicalalloyingcanlargelyincreasethesolidsolubilityofimmiscibleFe100-xCuxalloy.

UniqueelectronicandmagneticpropertiesforFe-Cusystem.

ThemechanismenhancedsolubilityofFe-Cualloyisnotclear.

StructuraltransitionsofmechanicallyalloyedFe100-xCuxsystemstudiedbyX-rayabsorptionfinestructurePhysicaB,305,135(2001)

ShiqiangWei,WenshengYan,YuzhiLi,WenhanLiu,JiangweiFan,andXinyiZhang

PhysicaB,393,249(2001)

MetastablestructuresofimmiscibleFeXCu100-Xsysteminducedbymechanicalalloying.

J.Phys.CM,9,11077(1997).

ShiqiangWei,HiroyukiOyanagi,CuieWen,YuanzhengYang,andWenhanLiu.

Preparations

AlloyompositionFe100-xCuxx=0,10,20,40,60,80,100.

WCballstothemixedFe-Cupowder10to1.

MAmillingrate:about210r/min.

ThestructureparametersofFe100-xCuxbyfittingtheFeK-edgeEXAFSspectra

ThestructureparametersofFe100-xCuxbyfittingtheCuK-edgeEXAFSspectra

RDFsofFe100-xCuxalloys

FittingresultsoftheFe100-xCuxsamples

9010

2080

F(r)

F(r)

k3(k)

k3(k)

90

10

80

20

80

20

60

0

60

0

0

60

0

60

30

70

30

70

20

80

Sample

Bond

type

R(Å)

(Å)

N

E0

Fepowder

Fe-Fe

248002

00700005

8005

297

Fe90Cu10

Fe-Fe

248002

00780005

7605

-401

Fe-Cu

248002

00800005

0703

-159

Fe80Cu20

Fe-Fe

248002

00810005

7205

-201

Fe-Cu

248002

00810005

1203

431

Fe60Cu40

Fe-Fe

257002

00990005

8705

064

Fe-Cu

256002

00990005

3503

-499

Fe40Cu60

Fe-Fe

258002

00990005

6905

499

Fe-Cu

258002

00990005

5605

263

Fe30Cu70

Fe-Fe

258002

00980005

5705

496

Fe-Cu

258002

00980005

6405

294

Fe20Cu80

Fe-Fe

258002

00980005

5005

495

Fe-Cu

258002

00980005

7105

345

Sample

Bondtype

R(Å)

(Å)

N

E0

Fe90Cu10

Cu-Cu

248002

00780005

1503

-31

Cu-Fe

248002

00730005

6705

-50

Fe80Cu20

Cu-Cu

250002

00820005

2103

48

Cu-Fe

249002

00810005

6205

40

Fe60Cu40

Cu-Cu

255002

00890005

7105

27

Cu-Fe

255002

00870005

4605

09

Fe40Cu60

Cu-Cu

256002

00890005

8405

-39

Cu-Fe

254002

00890005

3303

-43

Fe30Cu70

Cu-Cu

255002

00890005

9705

-18

Cu-Fe

254002

00890005

2303

-38

Fe20Cu80

Cu-Cu

255002

00890005

9805

-21

Cu-Fe

254002

00880005

1503

-46

Cupowder

Cu-Cu

255002

00890005

12.00.5

04

Conclusions

ThelocalstructuresaroundFeandCuatomsdependontheinitialcomposition.

Fe100-xCuxsolidsolutionsx40,fcc-likestructurex20,bcc-likestructure

40x20,bcc+fcc-likestructure

Thefittingresultsindicate

Forx40,theMAFexCu100-xalloysareinhomogeneoussupersaturatedsolidsolutions,andafccFe-richandafccCu-richregionsinsolidsolutions.

Forx20.TheevolutionoftheFTintensitiesandstructuralparametersofFeatomsisidenticalwiththoseofCuatoms.ThisresultsuggeststhattheCuatomsbealmosthomogeneouslyincorporatedintothebccFe-Cuphase.

FeCu FeK-edge

600

Fe60Cu40FeK-edge

500

400

300

200

100

6 8

Distance(A)

InsituXAFSathightemperature

InsituXAFSofGeNb3atlowtemperature

70

60

50

NiB

40

30

NiP

20

10

0 100 200 300 400 500

temperature/oC

3.1Catalyticactivitiesofnano-amorphousNi-BandNi-PforBenzeneHydrogenation

F(r)

F(r)

F(r)(Arb.units)

benzeneconversion/%

3

n ld

Ni-B

stlz

dNi-P

o o

nano-amorphousalloys

Significations

TM-MtypeUltrafineamorphousalloy(TM=Ni,Co,Fe;M=B,P)havethehighratioofsurfaceatomsandamorphousstructure.

Applicationsinferrofluid,catalystsandmagneticrecordingmaterials.

e

Chemicalmethod:B42mol/L

Ni(CH3COO)24H2O,0.25mol/L

ice-waterbathandvigorouslyagitatedbyamaneti tirrer.

3.2DTAprofilesofNiBandNiP

3.3XRDresultsofNiBwithdifferent

annealedtemperatures

773K

573K

30

40

50

523K

Ni-P(initial)

60 70

XRDspectraofNiPatdifferenttemperature

3.4XAFSresults

k3(k)-kfunctionofNiBandNiP

Ni

773

673K

573K

473K

Ni-P(intial)

-

k(nm-1)

2500

2500

2000

2000

1500

Nifoil

773K

673K

623K

573K

473K

Ni-B(initial)

0.81.0

Distance/nm

1500

Nifoil

1000

1000

500

500

773K

673K

573K

473K

Ni-P(initial)

0

0.81.0

Distance/nm

FITTING

B

773K

673K

573K

473K

NiB(initial)

K(nm

k(nm-1)

FittingresultsofNiBandNiP

FTAmplitude(a.u.)

FTAmplitude(a.u.)

dH/dT

Intensity/a.u

0.214nm

0.203nm

0.194nm

0.176nm

K3(K)

k3(k)

Intensity(arb.units)

o

(210)2.42A

(121)2.35A

o

o

(201)2.23A

(211)2.12A

o

o

(111)2.03A

(102)2.02A

o

(031)1.97A

o

k3(k)

o

(k)

(112)1.93A

o

(221)1.85A

o

(200)1.76A

(122)1.72A

(230)1.68A

(301)1.61A

o

o

AveragedistanceRj=R0+σsR’serror=0001nm，T’serror=00510-2nm，S’serror=0110-2nm。

SampleAnnealingPairRj(nm) R0(nm) NT(10-2nm)S(10nm)E0(eV)

Ni-B

Temp

25oC

Ni-Ni

02740241000111010

069

33

-02

Ni-B

0218021500012702

046

034

-47

Ni-P

25oC

Ni-Ni

02710243000110010

060

28

-29

Ni-P

022302150001

3

Ni-B

300oC

Ni-Ni

0255024300019910

060

11

-09

Ni-B

0218021500012602

060

034

50

Ni-P

300oC

Ni-Ni

02580242000110110

063

16

-13

Ni-P

022202150001

0802

049

065

87

Ni-B

500oC

Ni-Ni

024902450001

10810

070

039

16

Ni-B

021702150001

0302

056

023

-50

Ni-P

500oC

Ni-Ni

025502430001

10410

060

125

-28

Ni-P

022502190001

0602

040

056

76

Nifoil

Ni-Ni

0249

120

074

Conclusion

TheXAFSresultsdemonstratethatafcc-likenanocrystallineNiphasewithamedium-rangeorderisformedat573Kwherethefirstexothermicprocessisobserved.Themetastableintermediatestatesconsistofthetwophases,i.e.,nanocrystallineNiandcrystallineNi3Balloy.

WehavenotedthattheSofNi-Nissignificantlydecreasesfrom0.033to0.0029nm,afterNiBbeingannealedatthetemperatureof773K.ThestructuralparametersofNiBsampleisalmostthesameasthatofNifoil.Nevertheless,theS(0.0125nm)ofNiPsampleisratherlarger.

4dilutemagneticsemiconductors(DMSs)

4.1Ga1-xMnxNdilutemagneticsemiconductors

Appl.Phys.Lett.89,121901(2006)

Appl.Phys.Lett.88,051905(2006)Phys.Rev.B(InPress)

ModelstructuresofvariousrepresentativeMnoccupationsitesinGaNlattice

80S-substitutional I-interstitial

C-clusters

60 2.5%sample

S+I+C

40 S+I

20

S+C

10%sample

o

R(A)

XAFSresultsfortheGa1-xMnxNDMS

ModelstructuresofvariousMnoccupationsitesinGaNlattice

MnK-edgeXANESspectraofGa1-xMnxN

5

A

B

4

C

crystallineGaN

3

A1

B1B2

2

1

Ga0

00

20 40 60 80

Energy(eV)

ComparisonofXANESspectrabetweenexperimentsandcalculations

GaN

Mn

B1B2

Mn

A B

GaMnN

3A1

dimerGa0.975Mn0Ga0.900Mn0

Mncluster

20

40 60

Energy(eV)

80

MnK-edgeXANESspectraofdifferentMnsiteshavedistinctcharacteristicsandcanberegardedasadiscriminationofMnoccupationsinGaN.

34

34

K/nm-1

LowCoconcentrationsx≤0.05Core ceZnHighCoconcentrationsx≥0.10Co3O4

FT|k3(k)|

F/I0(Arb.Units)

|FT(K3(K))|(arb.units)

F/I0(Arb.Units)

|FT(