Phase Separation in Magnetic Oxides: Mesoscopic vs. Microscopic

1
Advanced neutron spectrometers for condensed
matter studies at the IBR-2M reactor
Anatoly M. Balagurov Frank Laboratory of Neutron
Physics, JINR, Dubna, Russia

• Neutron scattering for condensed matter
• science.
• IBR-2M pulsed reactor as a neutron source
• of third generation.
• Performance of neutron scattering
• spectrometers at the IBR-2M.
• Perspectives.

Hydrogen primary energy sources, energy
converters and applications
2
Neutron space and time domain
S(Q, ?) ??ei(Qr ?t) G(r, t)drdt
l 2p/Q, t 2p/?
For elastic scattering
?Q (10-3 50) Å-1 ?l (0.1 6103) Å
Nanostructured materials are inside!

• Neutron scattering features
• Strong magnetic interaction,
• Sensitivity to light atoms,
• Sensitivity to isotopes,
• Large penetration length,

3
Success of neutron scattering experiment depends
on
I. Parameters of a neutron source
average power, pulse width, spectral
distribution, ...
II. Performance of a spectrometer
intensity, resolution, (Q, E)-range, available
sample environment, ...
III. Team at spectrometer
head of team, experience, contacts, ...
4
Neutron sources for condensed matter studies
I. Continuous neutron sources
II. Pulsed neutron sources
W 10 100 MW Const in time
II-a. SPS
II-b. LPS
VVR-M, Russia IR-8, Russia, ILL, France LLB,
France BENSC, Germany FRM II, Germany BNC,
Hungary NIST, USA ORNL, USA SINQ, Switzerland
W 0.01 1 MW Pulsed in time ?t0 (15 100)
µs
W 2 5 MW Pulsed in time ?t0 (300 1000)
µs
ISIS, UK LANSCE, USA SNS, USA KENS, Japan J-SNS,
Japan
IBR-2M, Russia ESS, Europe LANSCE (new) ???
5
TOF high-resolution diffractometer at LPS type
source
Neutron pulse after fast chopper ?t0 (20 50)
µs
?d/d 0.001 for back scattering
6
HRFD High Resolution Fourier Diffractometer at
IBR-2
Put into operation in 1994 in collaboration
between FLNP (Dubna), PNPI (Gatchina),
VTT (Espoo), IzfP (Drezden)
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HRFD resolution
The utmost TOF resolution of HRFD
For V11,000 rpm L30 m
Rt0.0002 (0.0009 now)
Diffraction patterns of Al2O3 measured at ISIS
(UK) and IBR-2 (Dubna). Resolution is the same,
despite L is 5 times longer at ISIS.
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Neutron spectrometers on the IBR-2M reactor
Diffraction (6) HRFD, DN-2, SKAT, EPSILON,
FSD, DN-6 SANS (2) YuMO, SANS-C Reflectometry
(3) REMUR, REFLEX, GRAINS Inelastic scattering
(2) NERA, DIN
13 spectrometers (3 new)
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Spectrometers on existing pulsed neutron sources
Technique \ Source IBR-2(M) (Russia) ISIS (UK) IPNS (USA) LANSCE (USA) KENS (Japan)
Diffraction 6 (6) 8 (2) 4 6 5
SANS 1 (2) 2 (1) 2 1 1
Reflectometry 2 (3) 2 (3) 2 2 2
Inelastic Scat. 3 (2) 9 (1) 3 3 5
Total 12 (13) 21 (7) 11 12 13
At a new SNS (Oak Ridge) neutron source 18
spectrometers are planning
Numbers in brackets spectrometers at the II
Target Station
IPNS is closed in the very beginning of
January 2008
10
Diffraction at the IBR-2M

1. HRFD powders atomic and magnetic structure
2. FSD bulk samples internal stresses
3. DN-2 powders real-time, in situ
4. DN-6 microsamples high-pressure (new project)
5. EPSILON rocks internal stresses
6. SKAT rocks textures

Fourier RTOF technique Long (100 m) flight
pass
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Diffraction at the IBR-2M. Resolution.
HRFD powders FSD internal stresses DN-2 real-tim
e, multilayers DN-6 high-pressure EPSILON
stresses SCAT textures
Resolution becomes better for longer d-spacing!
12
2
1
No 1

1. Chamber of the cold moderator.
2. Light water pre-moderator.
3. Flat water reflector.
4. Outer border of the reactor jacket.

No4
4
20K
No 5
300K
No 6
water
3
No 9
Combi-moderator at the central direction of the
IBR-2M reactor, plan view
13
Cold moderators at the IBR-2M reactor
Gain factor as a function of ?
Diffraction patterns of TbFeO3 measured at
Tmod30 K and 300 K
Neutron flux distributions as a function of ?
14
HRFD development
Actual state
Resolution one of the best in the
world Intensity not high enough (Od0.2 sr)

1. Neutron guide
2. Detector array
3. Correlation electronics

Could be
Resolution best among neutron diffractometers Int
ensity 10 times better than now
500 KUSD
15
New diffractometer for micro-samples and
high-pressure studies
Chopper
Neutron guide
Sample
Actual state
Ring-shape detectors
Ring-shape multi-element ZnS(Ag)/6LiF detector
Resolution optimal for high-pressure
studies Intensity one of the best in the
world Pressure up to 7 GPa in sapphire anvils

1. Detector array
2. Neutron guide

Could be
Intensity 25 times better than now Pressure
20-30 GPa in natural diamond or mussonite
250 KUSD
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GRAINS complete reflectometry at the IBR-2M
reactor
FLNP M. Avdeev, V. Lauter-Pasyuk Germany H.
Lauter V. Aksenov, V.
Bodnarchuk PNPI V. Trounov, V. Ulyanov
Parameters
Resolution optimal, d?/? (0.3 7), angular
(1 10) Q-range optimal, (0.002 0.3)
Å1 Intensity one of the best in the world
Modes
Cost estimate 1050 kEUR Contributions -
Germany, Hungary, - Romania, external.

• Reflectometry in vertical plane,
• Off-specular scattering,
• GISANS with polarized neutrons.

17
A new reflectometer GRAINS at the IBR-2M reactor
Main feature vertical scattering plane ? studies
of liquid media
18
Frank Laboratory of Neutron Physics Condensed
Matter Department Proposals for IBR-2M
spectrometer complex development
program Editors Victor L. Aksenov, Anatoly M.
Balagurov Dubna, 2006
The second edition of the proposals is under
preparation.
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Proposals for 2008 2011
Development of existing spectrometers
New spectrometers
General-purpose projects

1. HRFD (SA)
2. FSD (SA)
3. DN-2
4. SKAT (BMBF)
5. EPSILON (BMBF)
6. YuMO
7. REMUR
8. DIN (RosAtom)
9. NERA (Poland)

1. DN-6
2. RTS
3. SANS-C
4. GRAINS
5. SESANS
6. SANS-P

1. Moderators
2. Detectors
3. Sample environment
4. Cryogenics
5. Electronics

2,700 K
3,000 K
4,000 K
In total 9.7 M for 4 years
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Priorities for 2008
Priorities for 2009 - 2011
Approved projects
Strategical necessity
YuMO / SANS-C
FSD DN-6
Projects with external support
Projects without clear perspective
REMUR, NERA, DIN, SESANS, SANS-P, DN-2, RTS
SCAT EPSILON GRAINS HRFD
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New science after 2010

• Modern material science
• - nanostructures (catalysts, multilayers, porous
  materials, ),
• - materials for energy (electrochemistry,
  hydrogen, ),
• - biomaterials, polymers (soft-matter),
• - new constructive materials for atomic energy,
• - geological problems (earthquakes, waste
  deposit, ),
• Modern fundamental physics
• - complex magnetic oxides with strong
  correlations,
• - low-dimensional magnetism,
• - phase coexistence in crystals,

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User program at the IBR-2 spectrometers
International experts commissions
Time-sharing (13 spectrometers)
FLNP (35)
I. Diffraction II. Inelastic Scattering III.
Polarized neutrons IV. SANS
External fast (10)
External regular (55)
User statistics
IBR-2 operational time 2000 hours/year Number
of experiments 150 per year External
users 100 per year
Others, 19
FLNP, 25
France, 3
Poland, 5
Germany, 17
Russia, 31
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Condensed Matter Department at FLNP
JINR staff 38 Member States staff 28
Professor 4 Doctor of science 10 Candidate of
science 26 Ph.D. students 11
1999 52 28 80 2007 38 28 66
What staff do we need?
CMD administration 4 Heads of directions
4 Group at spectrometer 3x13 39 Technical
group 5 Additional techniques
5 Scientific groups 10 67
Age distribution
There exists a substantial deficiency of
permanent staff personnel
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• IBR-2 is one of the best neutron sources in the
  world and the only existing advanced neutron
  source among JINR Member States.
• Existing spectrometers are comparable with that
  at other advanced pulsed neutron sources some of
  them are unique.
• Experimental potential of the complex is much
  higher than that existing now.
• All spectrometers are accessible for
  international community in a frame of accepted
  proposals.
• Period 2008 2010 is most convenient for global
  development of neutron spectrometers.
• Adequate financial support is urgently needed.

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Ambitious goal for Condensed Mater Department,
Frank Laboratory of Neutron Physics, and Joint
Institute for Nuclear Research
Experimental complex based on the IBR-2M reactor
for fundamental and applied investigations of
advanced and nanostructured materials.
26
From White-Egelstaff law-book for thermal
neutron scattering (1970)

• Law 2
• Neutrons are to be avoided where there is an
  alternative!

New version Neutrons can be applied everywhere,
even if an alternative there exists!
For studies of nanostructured materials as well !
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Thank you !
28
Neutron spectrometers on the ISIS spallation
source (RAL, UK)
Diffraction (8) GEM, HRPD, PEARL, POLARIS,
ROTAX, SXD, ENGIN-X, INES SANS (2) SANDALS,
LOQ Reflectometry (2) CRISP, SURF Inelastic
scattering (9) HET, MAPS, MARI, MERLIN, PRISMA,
IRIS, OSIRIS, TOSCA, VESUVIO
21 spectrometers
29
from MEETING REPORT Consultancy on the Status of
Pulse Reactors and Critical Assemblies IAEA, 16
18 January 2008
The IBR-2 reactor at Joint Institute on Nuclear
Research, Dubna is a unique facility
internationally, and is being refurbished/moderniz
ed to continue to serve as an international
centre of excellence for neutron sciences.
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Diffraction at the IBR-2M. Intensity.
Mo powder measured in 1 min (1) and 0.2 sec (2).
Intensity / Counting rate
I F0 S O/4p d n/s 106 n/s
F0 neutron flux at a sample, 107 n/cm2/s S
sample area, 5 cm2 O detector solid
angle, 0.2 sr d scattering probability,
0.1
31
IBR-2M pulsed reactor (with cold moderators) is
the source of third generation)
Source Parameter SNS, USA (SPS) JSNS, Japan (SPS) IBR-2M, JINR (LPS) ESS, Europe (LPS)
Status 2008 2009 2010 2015 ?
Power, kW 1200 1000 2000 5000
Pulse width, µs 15 - 100 15 100 350 1000 ?
Frequency, s-1 60 25 5 gt20
) For 2nd generation sources W is between 6
200 kW (IPNS, KENS, LANSCE, ISIS)
32
Resources which are needed to complete the 2007
- 2010 program
Technical needs 1. Neutron guides 300
m 2. 1D PSD 5 3. 2D PSD 4 4.
Large aperture det-s 6 5. Choppers
6 6. Neutron optics devices 7. Spin analyzers
polarizers 8. Electronics computing 9. Sample
environment refrigerators, thermostats, magnet
s, acoustic technique
Financial needs (in KUSD) A. Development (9)
4,105 (456) B. New projects (6) 2,991
(499) Total (15) 7,096
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Hydrogen materials what can we learn with
neutrons?
Location of H, OH, H2O in crystal coherent
elastic, diffraction. Dynamics of H, OH in
crystal incoherent inelastic. Diffusion of H,
H2O in solids or liquids quasielastic
incoherent. Clustering of H, nanostructures cohe
rent elastic, SANS. Exchange membrane,
hydration/dehydration diffraction,
reflectometry. Quantitative analysis incoherent
scattering / absorption.
H (and Li) are the most important Elements for
fuel cells and batteries!
Proton exchange membrane
34
Phase transformations of high pressure heavy ice
VIII. Time-resolved experiment with ?t (1 5)
min.
Ih
Ice VIII
Ic
hda
Time temperature scale
TOF scale
Time / temperature scale Tstart94 K, Tend275
K. The heating rate is 1 deg/min. Diffraction
patterns have been measured each 5 min. Phase
VIII is transformed into high density amorphous
phase hda, then into cubic phase Ic, and then
into hexagonal ice Ih.
35
Investigation of strain/stress and texture on
geological samples
Project EPSILON/SKAT
Spokesman from JINR Dr. Ch. ScheffzükSpokesman
from Germany Dr. habil. A. Frischbutter
EPSILON-MDS
SKAT
New neutron guide
Could be
106 EUR
Intensity 10 times better than now
36
Diffraction at the IBR-2M. General conclusion.
Unique complex with world top opportunities
in - extremely high-resolution (HRFD), -
extremely high-intensity (DN-6, DN-2), - applied
studies (FSD, EPSILON, SKAT).
37
Polarized neutron scattering at the IBR-2M

• REMUR magnetic multilayers magnetic structures
• 2. GRAINS interface science in physics, biology,
  chemistry
• (new project)
• 3. REFLEX reflectometry in horizontal plane,
• now is used in test mode

38
Resolution at pulse neutron source. Elastic
scattering.
R (?t0/t)2 (??/tg?)21/2
For ?t0 350 µs, L 25 m, ? 4 Å TOF
contribution is 1. Geometrical contribution
is (0.05 0.2) for back scattering (5
10) for SANS and reflectometry
TOF component in resolution function is not
important for SANS and Reflectometry It is not
very important for single crystal diffraction,
magnetic diffraction
Powder diffraction structural studies, stress
analysis, low symmetry textures?
39
Criteria which could be used for the evaluation

1. Modern and interesting science.
2. Correspondence to the IBR-2M features.
3. Top level parameters.
4. Active and effective team.
5. External support (financial, technical, ).

40
Proposals at the IBR-2 reactor, JINR, Dubna
IBR-2 operational time 2000
hours/year Number of experiments 150 per
year External users 100 per year
41
Research reactors in the JINR Member States
Russia
Czechia
I. Dubna, IBR-2 (1984, 2 MW, pulsed) II. RCC
KI Moscow, IR-8 (1957, 8 MW) III. Gatchina,
VVR-M (1959, 16 MW) IV. Yekaterinburg, IVV-2M
(1966, 15 MW) V. Obninsk, VVR-M (1960, 12 MW)
I. Rez, LVR-15 (1970, 10 MW)
Germany
I. Munich, FRM-II (2005, 20 MW) II. Berlin,
BENSC (1973, 10 MW)
Hungary
I. Budapest, BNC (1970, 10 MW)
The enhanced flux and new instrument concepts
will allow to improve the resolution in both
space and time gt new science!
42
Neutron Techniques (developed at the
IBR-2) DINS Deep Inelastic Neutron
Scattering INS Inelastic Neutron
Scattering LND Laue Neutron Diffraction NBS Neut
ron Back-Scattering ND Neutron
Diffraction NHol Neutron Holography NI Neutron
Interferometry NPol Neutron Polarimetry NRad Neu
tron Radiography NRef Neutron Reflectometry NTom
Neutron Tomography NSE Neutron
Spin-Echo PolN Polarized Neutrons PST Phase-Spac
e Transformation QENS Quasi-Elastic Neutron
Scattering SANS Small Angle Neutron
Scattering TAS Triple-Axis Spectrometry TOF Time
-Of-Flight (techniques) USANS
Ultra SANS ZFNSE Zero-Field NSE
At the IBR-2 the techniques are developed, which
are the most effective for condensed matter
studies and above all for studies of
nano-structured materials.