Synchrotron Radiation based TDPAC

Synchrotron Radiation based TDPACI. Sergueev

European Synchrotron Radiation FacilityGrenoble, France

HFI / NQI 2010, 12-17 September 2010 CERN

ESRF

CERN

Outline

• SR TDPAC: comparison with conventional TDPAC •SR TDPAC: comparison with MS and NRS

• Examples of application:

• Site-specific phonon dynamics

• Relaxation in glasses

• Study of QI in -tin

• Conclusion


Nuclear Resonance Scattering


ground state

excited state

life time of the excited state - 0

absorption re-emission

Time

0 200 ns

Time

A.Q.Baron et al, Europhys. Lett.,34, 331(1996)

I.Sergueev et al, Phys. Rev. B 73, 024203 (2006)I.Sergueev et al. Phys. Rev. B 78, 214436 (2008)

TDPAC vs SR TDPAC


1

2

β-,β+,EC

TDPAC

1 2

SRPAC

1 2

sample(-source)

counterstart stop

detector 2

12 detector

SR

start stopcounter

sample

Advantages of SR TDPAC:•no chemical or electronic aftereffects•only one nuclear transition•in general, large contrast of the beats

dete

ctor

1

Formal description of SR TDPAC for M1


Z

kin

kout

Z

k1

k2

TDPAC

)()(cos1)( 22222/ tGPAetI t )()(cos21)( 22222

/ tGPAetI t

Isotope transition 2A22

57Fe, 119Sn 1/23/21/2 0.5

61Ni, 155Gd 3/25/23/2 0.28

121Sb, 151Eu

5/27/25/2 0.22

99Ru 5/23/25/2 0.02

SR TDPAC

SR TDPAC on 57Fe


Z

kin

kout

0 50 100 150

200

400

600

Time / ns

Inte

nsity

/ co

unts

200

400

600

200

400

600

Sample: ferrocene enriched by 57Fewith quadrupole splitting

ttG cos)( 54

51

22

)()(cos21)( 22222/ tGPAetI t

Sample: α-iron enriched by 57Fewith magnetic splitting

0 100 200 3000

100

Inte

nsi

ty /

counts

Time t / ns

Z

kin

kout

B

)(21)( 22/ tRAetI t

ttR B2cos)( 43

41

1 2

3

1

2

3

SR TDPAC for E2 transition


Nuclear transition : 0+ 2+, Cascade: 0 2 0

0 1 2 3 4 5 60

1

2

Rela

tive Inte

nsi

ty

Time t / ns

166ErFe6Sn6

D. H. Ryan and J.M.Cadogan, Hyp. Int. 153 (2004) 43

)4cos)(cos)(cos()(

)(cos)(21)(

)4(424

1444444

1

22222/

PPtGA

PtGAetI t

Experimental setup


Monochromator

High ResolutionMonochromator

Al foilUndulator

Sample

Detector

Detector

beam

Detector with Si APDs

APD

Dynamical range: ~106 ph/sTime resolution: ~0.1-2 ns

Energyband width:

1-30 meV

SR TDPAC vs NFS


k0

t = 0 t = 0

k0

k1

t > 0

nuclear bragg diffraction

single nucleus scatteringSR TDPAC

k0

t > 0

coherent scattering in forward direction -

- nuclear forward scattering

Optical theorem:

t f wd( ) I m Fourier f (t) MS total cross-section

NFS amplitude

Differences:• dependence on the spatial evolution of nuclei• dependence on the ground nuclear state spin evolution

Hyp. Int.: quadrupole splitting

0 200 400 600

NFS

I(t)

Time t (ns)

SR TDPAC

-2 0 2 Velocity [ mm/s ]

Rela

tive

tra

nsm

issi

on

MS

i t i tE e e

Coherent superposition of the wavelets

I=3/2

I=1/2

Energy level diagram: 57Fe, quadrupole splitting

|m|3/2

1/2

1/2

Ferrocene


Hyp. Int.: 2 single lines

0 200 400 600

NFS

I(t)

Time t (ns)

SRPAC

-2 0 2 Velocity [ mm/s ]

Rela

tive

tra

nsm

issi

on

MS

I=3/2

I=1/2

SR TDPACMS, NFS


Hyp. Int.: magnetic splitting

0 100 200 300

NFS

Log

I(t)

Time t [ ns ]

SR TDPAC

-8 -4 0 4 8 Velocity [ mm/s ]

Rela

tive

tra

nsm

issi

on

MS

-ironm

+3/2+1/2-1/2-3/2

-1/2+1/2

MS, NFS

SRPAC


SR

SR TDPAC

NFS

Applications

• Site-specific phonon dynamics

• Relaxation in glasses

• Study of QI in -tin

Phonon assisted SR TDPAC


Weber, H., Hafner, S.S.: Z. Krist. 133 (1971) 331.

A site: tetrahedral, B = 49.0 T

B site: octahedral, B = 46.0 T

Handke B et al., Phys. Rev. B 71 (2005) 144301Sample:Magnetite, Fe3O4

Phonon assisted SR TDPAC


)(21)( 22/ tRAetI t

)2cos()2cos()( 43

41

43

41 tBtAtR BA

B site

A site

16 meV22 meV

35 meV

0

1

A=0.5, B=0.5

A=0.6, B=0.4

A=0.8, B=0.2

0

1

Ani

sotrop

y

0 50 100 150 2000

1

Time / ns

Relaxation in glasses


EFG

ferrocene Fe(C5H5)2

Sample:

Glass-former:Di-butyl phthalate, Tg = 178 K

Task: resolve rotational and translational degrees of motions



Relaxation process

a aα

α

λ

k – jump rate, sec-1

a – jump distanceα – jump angleλ – wave length, 0.86 AR – radius of the molecule, 2 A

22

32

akT

223 kR

R

a 3

2

03.02

232

RT

R



1000

2000

1000

2000

1000

2000

Inte

nsity

T = 180 K

1000

2000

500

0 100 200 300 400 500 600101

102

Time / ns

T = 280 K

102

103

101

102

T =205 K

Inte

nsity

0 100 200 300 400 500 600100

101

102

103

T =215 K

Time / ns

T =180 K

Sample:

Di-butyl phthalate, Tg = 178 K

Di isobytyl phthalate, Tg = 188 K5% ferrocene +

DiBP+FCSR TDPAC

DiBP+FCNFS

SR

SR TDPAC

NFS



140 160 180 200 220 240 260 280 300

105

107

109

SR TDPAC NFS + MS

NR

S d

ampi

ng /

s-1

Temperature / K

DS

rat

e / s

-1

105

107

109

dielectric spectroscopy J .Phys.Chem.B 108(2004)4997

140 160 180 200 220 240 260 280 300

105

107

109

NR

S d

ampi

ng /

s-1

Temperature / K

SR TDPAC NFS + MS

105

107

109

DS

rat

e / s

-1

dielectric spectroscopy J .Phys.Chem.B 108(2004)4997

DBP+FC DiBP+FC

Conclusions:The probe reproduces the dynamics of the glass former.At low T dynamics of the probe follows slow β branchAt low T only molecular rotation is seen in both NFS and SR TDPAC.

Study of -tin by SR TDPACC. Strohm et al., in preparation

K.P.Mitrofanov et al., Sov. Phys. JETP 21 (1965) 524

0 100 200 300 400100

101

102

103

104

Time / ns

90 K

105

Inte

nsi

ty / c

ounts

190 K

104

105

295 K

104

105

573 K

0 100 200

0.8

1.0

1.2

Time / ns

0.8

1.0

1.2

0.8

1.0

1.2

Anis

otropy

0.8

1.0

1.2

Measurements by SR TDPAC


J.C. Soares et al.,Phys.Lett. 45A(1973)465

Study of -tin by SRPAC

1970 1975 1980 2008

17.5

18.0

18.5

19.0

Deca

y half

time /

ns

Year of measurements

Nuclear Data Sheets value: 1/2

= 18.030.07 ns

Result of SRPAC measurements:1/2

= 18.290.01 ns

Results of measurements

0 100 200 300

0.24

0.26

0.28

0.30

0.32

this measurements previous MS and TDPAC

measurements

Qua

drup

ole

split

ting

/ mm

/s

Temperature / K

Conclusion:•value of the life time of 23.9keV nuclear state of 119Sn was obtained with high precision•quadrupole splitting of -tin have been seen in the time spectrum and was measured for different temperatures


Conclusion

SR TDPAC – method which allows to extend study of hyperfine interactions by TDPAC on to Mössbauer isotopes

– method which allows to extend study of hyperfine interactions by MS into the range of zero Lamb-Mössbauer factor.

3 main directions of application:

Complementary to MS information about hyperfine splitting and dynamics

Hyperfine interactions in high energy Mössbauer isotopes

Study of hyperfine interactions and dynamics in soft condensed matter


Acknowledgment


• U. Van Bürck – TU München, Germany• G. Smirnov – Kurchatov Institute, Moscow, Russia

Members of ESRF nuclear resonance group:• R. Rüffer• A. Chumakov• T. Asthalter• C. Strohm•T. H. Deschaux-Beaume

Synchrotron Radiation based TDPAC

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