Bilan Activité 2007-2009
Structure et Propriétés des Matériaux-Conditions Extrêmes
Permanents
M. Anne (DR, 05), P. Bordet (DR, 05), N. Boudjada (MCF UJF, 28), C. Colin (MCF UJF, 28), C.
Darie (MCF UJF, 33, HDR), E. Dooryhee (CR, 05, HDR), J-L. Hazemann (DR, 18), J-L. Hodeau
(DR, 05), O. Isnard (PR, UJF, 28), H. Klein (MCF, UJF, 28), P. Martinetto (MCF, UJF, 28), P.
Strobel (DR, 15), D. Testemale (CR, 18), P. Toulemonde (MCF, UJF, 28)
Non permanents
D. Bhange (Post-doc CNRS), C. LePoittevin (Post-doc CNRS), M. Gemmi (associate researcher,
CNRS), H. Muguerra (Post-doc ANR), S. Zouari (CDD Région Rhône-Alpes), I. Chicinas (CDD
Région Rhone-Alpes)
PHD students
P. Carvalho-Sarvezuk (cotutelle Brésil-UJF), N. Coroian (Co-tutelle Roumanie), C. Da Silva (BDI,
INPG), C. Dejoie (Région, UJF), J. James-Smith ( Co-tutelle Australie-UJF), K. Marty (Ministère,
UJF), H. Mayot (Ministère, UJF),T. Mendonca (Co-tutelle Portugal-CERN-UJF), B. Neamtu (Cotutelle Roumanie-UJF), S. Oliveira-Neto (Co-direction Brésil-UJF), Phung Le (Co-tutelle Région
Rhône-Alpes-INPG ), F. Popa (Co-tutelle Roumanie-UJF)
Abstract : We focus our research on the understanding of the physico-chemical properties of complex
materials based on the precise description of their structures. These studies are conducted on a wide
range of materials (see keywords below). To fulfill its activity on magnetic materials the group has been
recently reinforced with C. Colin (MdC-UJF). The skills and expertise within our team range from the
conception and preparation of materials, to detailed structural studies using electronic diffraction &
microscopy, absorption & diffraction of X rays, neutron scattering. Our efforts are also dedicated to in situ
studies under high pressure and high temperature, with the purpose to understand structural and magnetic
phase transitions, meta-stable phases and reaction processes. To fulfill these goals the group is strongly
involved in the french CRG beamlines of large facilities (ESRF and ILL). Moreover, an important aspect of
our approach consists of developing original methods of structural analysis (resonant contrast, pair
distribution functions, electron crystallography, etc.) and instrumentation (high pressure synthesis setups,
autoclaves for in situ studies under high pressure and high temperature, mobile diffractometer, multianalyzer, etc.). To reinforce its activity on high pressure studies on liquid systems using synchrotron
facilities, the team has also been reinforced with D. Testemale, CR-CNRS. Those topics need a strong
collaboration with the technical groups within the department MCMF, and especially the Instrumentation and
CRG technical groups. The group also maintains and initiates numerous collaborations within the department
and Neel Institute, national and international as well
Keywords : Crystallography, Oxides, Intermetallics, Pharmaceuticals, Cultural heritage, Multiferroics,
Superconductors, Supercritical fluids, In situ studies under HT-HP, perovskite nanostructures.
New methods in structural analysis
We have a well-established expertise in structural
analysis using a large panel of techniques implying
laboratory as well as large facilities instruments. Our
activities extend from the solution of complex structural
problems related to internal or collaborative research
topics, to the development of methods and test of their
applicability. We are strongly involved in various higher
level teaching activities related to these topics (schools,
workshops…).
Analysis of complex structures from powder data
M. Anne, P. Bordet, E. Dooryhee, J-L. Hodeau,
P. Martinetto
Standard x-ray powder diffraction (XPD) has intrinsic
limitations, especially the difficulty in discriminating
between elements with similar atomic numbers or
occupying neighboring sites. To improve the efficiency
of XPD, we have developed the concept of direct
Institut Néel
localization of atoms in mixed-occupancy powders by
resonant contrast. The use of “dispersive difference”
electron density maps allows an easy localization of the
resonant atoms. The use of “anomalous difference
patterns” enables an accurate site localization. These two
specific difference tools can also be used with
multiphase powders.
When the local and average structures differ, or for
powder samples with nano-sized grains, the Pair
Distribution Function analysis (PDF) of powder
diffraction data is the technique of choice to obtain
quantitative local structural and micro-structural
information. We have tested and applied this technique
to various structural problems, as for example: TiO 2
nano particles for solar cells (collab. CSIRO Minerals,
Melbourne), allophane alumino-silicate nanostructures
(collab. CEREGE), local structure of BiMO 3
multiferroics, etc... We have especially studied the
experimental and PDF extraction procedures in the case
1
SPM-CE
of laboratory data, where this technique could become an
important characterization tool in the growing field of
nano-chemistry.
Pharmaceutical developers are more and more concerned
by solid form of drugs because it dictates their
properties,
including
stability,
hygroscopicity,
dissolution rate, solubility, and bioavaibility. These
solids can be molecular crystals (often prepared as
polycrystalline powders) or noncrystalline solids (less
stable but often with desirable pharmaceuticals
properties, such as faster dissolution rates). In the recent
years, advances in methodology have enabled to
characterize both solid forms using only XPD data.
Structures of polymorphic forms of some molecules have
been solved ab initio in order to understand the related
mechanism of growth between the different phases.
(research contract with Tech. Servier). An example is the
molecular compound (±) modafinil, known to crystallise
in five pure polymorphic formsi, some of which had be
solved using XPD. Other studies were devoted to a
special steroid derivative molecule (STNH), known to be
an efficient organogelator of saturated alkanes ii. The
crystallographic behavior of different xerogel forms were
now observed ex- and in-situ using XPD to solve
structures with conventional and global optimization
methods.
X-ray Tomo-diffractometry
E. Dooryhee, J-L. Hodeau
The advent of nanosciences calls for the development of
local structural probes to characterize real ill-ordered or
heterogeneous materials. We recently demonstrated the
potential of x-ray diffraction tomographyiii applied to
heterogeneous samples containing unknown, illcrystallized or nano-sized phases. It was used for
example on fullerene transformed at high pressure into
amorphous /crystallized diamond and on a
polycrystalline quartz-chalcedony sample containing iron
Mapping of phases in a C60 sample crushed under HP
using x-ray diffraction tomography
pigments inclusions. This method allows the
reconstruction of selective images of each phase and the
extraction of its diffraction diagram using an inverse
analysis. The overall detection sensitivity is better than
0.1%. It can be coupled to absorption and fluorescence
tomography yielding a ‘multimodal’ non-destructive
analysis with a large range of applications in materials,
2
environmental and medical sciences, paleontology and
study of artworks.
Electron crystallography
H. Klein, M. Gemmi, P. Martinetto, C. LePoittevin
Electron crystallography has been developed to
complement the ‘classical’ X-ray and neutron diffraction
for the solution of unknown crystal structures. The
acquisition of a precession electron diffraction (PED)
unit mounted on our Philips CM300ST transmission
electron microscope (TEM) in 2007, permits us to
overcome the limitations of electron diffraction caused
by multiple diffraction and thus to benefit fully from the
advantages of single crystal diffraction on nanometer
sized particles versus powder diffraction.
Comparison of the [1 0 0] zone axis of the LiTi1.5Ni0.5O4
structure obtained in SAED (left) and PED (middle). All
12 independent atom positions where obtained from
PED data, including the 4 O and 2 Li positions (right).
This is especially important in the prominent activity of
MCMF of synthesis of new materials in HP/HT
conditions or by solution chemistry where only (impure)
powders can be obtained. This new technique has been
validated on simple structures (Mn2O3, AgCoO2) and has
yielded important results on unknown structures that
could not be solved by X-ray powder diffraction, even
using synchrotron radiation (PbMnO2.75, LiTi1.5Ni0.5O4).
Perovskite oxide films and superlattices
E. Dooryhee, J-L. Hodeau
In the field of ferroelectric multilayers, we focused on
PbTiO3-based superlattices. In PT epitaxial films, the c
polar axis can be normal or parallel to the interface. In a
periodic multilayer, PT experiences either tensile or
compressive interfacial strains. Using the 7-circles
diffractometer at beamline ESRF-BM02, we investigated
the effects of strain and formation of domains by
modeling of (00L) line profiles and reciprocal space
mapping. We show that strain relaxation in PMN/PT
superlattices generates unusual domain patterning,
affecting Curie temperature and tetragonality of PTiv.
Adjusting the thickness ratio of PMN and PT layers
provides a way to control the polarization axis in very
thin ferroelectric layers.
Instrumentation and in-situ techniques
As for new methods, we are always keen to apply our
experience and skills to the development of original
instrumentation, ranging from ancillary equipments for
diffraction (cryostats, furnaces…) to synchrotron beam
line instrumentation. This is achieved thanks to tight
collaboration with the Instrumentation and CRG
technical groups.
Institut Néel
SPM-CE
High Pressure and High Temperature spectroscopy
autoclave developments
C. Da Silva, J-L. Hazemann, D. Testemale
A high pressure/high temperature cell dedicated to x-ray
absorption spectroscopy, small angle x-ray scattering,
and inelastic x-ray scattering techniques has been
developed and is constantly improved with the support of
the Instrumentation and CRG technical groups. The P
and T parameters are controlled independently and their
range allows the study of aqueous solutions (T<600 °C
and P<2000 bar) and liquid metals and glasses
(T<1700°C and P<2000 bar). Original high pressure
windows have been designed to ensure both pressure
resistance and low absorbance combined with large
angular aperture. The various materials used for the
windows and the internal cell that contains the sample
make this cell very versatile. It is successfully used in
several configurations: XAS, SAXS, Inelastic Raman
and Compton X-ray scatteringv.
lead by P. Bordet and regrouping researchers from the
SPM-CE, MatONLP, SFCE (MCBT) teams, the Cristaux
Massifs technical group and the LPCML (Lyon). Four
PhD theses at Institut Néel are partly or totally concerned
with this topic. Rare earth langasites, containing kagome
lattices of magnetic cations, were investigated to reveal
the effects of topological frustration, especially using
neutron scattering. Iron containing langasites were
shown to display a doubly chiral magnetic order related
to the structural chiralityix. The appearance of
multiferroism at the magnetic transition was investigated
by dielectric and structural measurements.
A portable diffractometer for art and archeology
P. Bordet, E. Dooryhee, J-L. Hodeau
The two frustrated magnetic sublattices in langasites
The analysis of artworks or archeological objects is
increasingly demanding for on-site measurements. In
collaboration with the C2RMF (Musée du Louvre,
Paris), we have designed a new portable x-ray
diffractometer based on a lightweight CuK x-ray source
and an image plate detector, combined with a
fluorescence detector for elemental analysisvi. To
minimize fluorescence background problems inherent to
area detectors, we have invented a new type of analyzer,
made of a large doubly curved conical crystal placed
between sample and detector and diffracting out of the
equatorial plane. The double curvature provides
fluorescence rejection for a wide 2 range and a large
angle of collection from the sample, allowing improved
data collection times. A prototype of the instrument has
been tested successfully and the doubly curved analyzer
has been patentedvii.
Oxides in magnetic and strongly correlated electron
systems
Oxides provide an immense range of experimental
examples of complex physical properties. Our group's
interest focuses mainly on relations between structure,
crystal chemistry and physical properties in correlated
electron and magnetically frustrated systems. It includes
an important activity in synthesis (ceramic and single
crystal samples), using standard techniques as well as
solvothermal and high pressure ones, and structural
investigations using TEM, x-ray and neutron diffraction.
Langasites
P. Bordet, C. Darie, K. Marty
The langasites form a large family of isostructural
compounds, essentially studied for their piezoelectric,
laser and NLO properties. We noticed that some
langasites contain sublattices of magnetic ions that could
lead to topological frustration and thus undertook the
study of their magnetic propertiesviii. This was the
subject of a 4 year ANR blanc contract accepted in 2006,
Institut Néel
Magnetically frustrated systems
C. Colin, C. Darie, O. Isnard, H. Muguerra, S. de
Oliveira Neto, P. Sarvezuk, P. Strobel
We are pursuing a strong activity in synthesis and
physical/structural studies in the field of topologically
frustrated magnets, both for 2D and 3D lattices (coll.
LNCMI, IN-MCBT, LPS…). We thus prepared high
quality powders of ANiO2 (A = Li, Na) for the study of
S=1/2 spin excitations and effects on the orbital and
magnetic ordering of Mg doping on the A site. x.
The Na-Co-O layered system attracted wide attention
because of the discovery of superconductivity in the
hydrated phase Na0.3CoO2•1.3H2O. As part of an ANR
'blanc' project , we studied Co substitutions and Na+
exchange. We have obtained a new form of 2H
AgCoO2xi, and showed that cobalt doping by Fe, Ni, Ru
makes water intercalation more difficult and suppresses
superconductivityxii.
In the trirutile ATa2O6 family, the topology of the
transition metal planes offers frustration of the exchange
interactions. We studied the crystal and magnetic
structures of the AxA’1−xTaO6 (A, A’ = Fe, Ni, Co)
system by magnetic measurements, XPD and NPDxiii.
We observed different magnetic structures resulting from
the competition between magnetocrystalline anisotropy
and frustrated exchange interactions.
The A2B2O7 pyrochlores provide good examples of 3D
topological frustration. We prepared new members of
this family by combining diamagnetic B/B' cations to
form R2B3+B'5+O7 pyrochlores (B = Sc, Ga, In; B' = Nb,
Sb). None of the new phases obtained (with R = Pr–Dy)
exhibits magnetic ordering down to at least 2 K xiv.
BiMO3 Multiferroics
P. Bordet, C. Darie, T. Mendonca, P. Toulemonde
Among the multiferroic materials, the BiMO3 distorted
perovskites (M= Mn3+, Fe3+, Cr3+) are promising for
applications. The Mn and Cr bulk compounds can only
be obtained under high pressure-high temperature
conditions. In 2007, new structural investigations of
BiMnO3 challenged the initial non-centrosymmetric C2
3
SPM-CE
space group, proposing instead a C 2/c symmetry that
prevents ferroelectricity. Furthermore, no information
about the magnetic structure of BiCrO3 was available.
We have synthesized powders and single crystals of
BiMnO3 and powders of BiCrO3 at HP-HT. For BiCrO3,
we combined electron microscopy, PDF analysis of
synchrotron data and NPD to show that the symmetry is
C2/c. We demonstrated that G-type antiferromagnetic
order appears at 114K, with progressive spin
reorientation between 80K and 60Kxv. BiMnO3 was also
investigated by PDF analysis and single crystal x-ray
diffraction.
within the metallic crystal lattice. In collaboration with
V. Paul-Boncour CNRS Thiais, we have investigated by
NPD the RFe2Dx R=Y, Tb compounds, in order to follow
the thermal stability of the deuteride. The stability of the
different interstitial sites has been discussed based on the
in situ study of the hydrogen desorption process. The
thermal evolution of the magnetic structure is also
determined
showing
a
competition
between
ferromagnetic and anti-ferromagnetic interactions,
leading to different magnetic ordering versus
temperature and hydrogen composition.
Magnetic and superconducting intermetallics
Iron-base superconductors
P. Bordet, P. Strobel, P. Toulemonde
Understanding the relations between crystal structure and
magnetic/superconducting properties of intermetallic
compounds is one of the main motivations for
investigating these systems. Our activity ranges from
chemical synthesis to physical characterization and
structural
investigation
using
complementary
experimental techniques.
One year ago, the discovery of high temperature
superconductivity in rare earth iron oxy-arsenides has
received a huge interest in the community of condensed
matter physics. Using HP-HT, we have synthesized
LnFeAs(O1-xFx) with Ln = La or Sm [family Ln-1111]
and (Ba1-xLax)Fe2As2 superconducting compounds.
Substituting F or La in these two compounds induces an
Intrinsic magnetic properties of intermetallic
compounds: R-Co-B et RCo5-xMx (M=Ga, Al, Si,)
C. Colin, N. Coroian, O. Isnard, H. Mayot
The Rn+1Co3n+5B2n compounds present a large variety of
crystalline superstructures deriving from the RCo 5 type
by an ordered substitution of boron for cobalt. We
determined the magnetic phase diagram of these
compounds versus temperature, composition, pressure
and magnetic fieldxvi. The influence of the hybridization
between the metalloid and transition metal electronic
states was studied at microscopic and macroscopic scales
by combining high magnetic field measurements,
neutron diffraction and different spectroscopies: Fe
Mössbauer, XAS or inelastic neutron scattering.
Nanocrystalline soft magnetic materials
O. Isnard, I. Chicinas, B. Neamtu, F . Popa,
The best soft materials nowadays are nanocrystalline
melt spun ribbons. In the seek for alternative method,
nanocrystalline powders of intermetallic alloys have
been obtained from mechanical alloying technique using
high energy milling and subsequent heat treatment to
release the internal stresses. We focus on the
optimisation of the synthesis conditions vs
microstructure of Ni based alloys for soft magnetic
potential applications among which one can cite Ni3Fe,
permalloy and supermalloy. The microstructures were
studied by x-ray and neutron diffraction and correlated to
the intrinsic magnetic properties.
Magnetism of hydrides
C. Colin, O. Isnard
We are interested in analysing the influence of hydrogen
insertion on the intrinsic magnetic properties of
intermetallic phases containing rare-earth and transition
metalxvii, mainly iron. From the determination of the
magnetic phase diagram of the starting compound and
corresponding hydride we can determine the influence of
H insertion on the magnetocrystalline anisotropy,
exchange interactions… Inelastic neutron spectroscopy
was also used to investigate the dynamic of H atoms
4
Crystallographic structures of doped LnFeAsO,
AEFe2As2 and FeSe elaborated superconductors.
electron doping of the parent systems which become
superconducting. For 10 % of fluorine La-1111 and Sm1111 superconduct at Tc = 20K and 45 K respectively. In
the Ln-1111 family we tried to introduce chemical
pressure by replacing arsenic by phosphorous and
studied the LnFe(As1-xPx)O solid solution, comparing the
effects on the structure and Tc with those obtained by
mechanical pressure on the pure compound xviii. We
studied the analogous superconducting family based on
iron in chalcogen tetrahedron FeCh4, Ch = Se, Te. The
properties of Fe1+(Se1-xTex) compounds obtained by HPHT synthesis or sealed tube method were compared at
room pressurexix. Our samples were also studied by
XRD under high pressure and resistivity under pressure
at low temperature.
Supercritical fluids and hydrothermal solutions
This research topic concerns the relations between
physical properties and structural organization in liquids
at extreme pressure and temperature conditions, up to
and beyond the critical point. Its main purpose is to
understand the structural basis of the increased reactivity
of liquids at supercritical conditions, specifically their
solvatation power. We apply our expertise to the
geochemisty field to determine structural properties
governing the transport of metal in hydrothermal fluids.
We essentially use in situ x-ray and Raman spectroscopy
techniques, mainly at ESRF and particularly on the
FAME beamline. We have developed a strong expertise
in the design of HP-HT cells for liquids.
Institut Néel
SPM-CE
Aqueous solution under supercritical conditions
C. Da Silva, J-L. Hazemann, D. Testemale
The study of HP-HT aqueous solutions is of particular
interest in the domain of life, earth and environmental
sciences. In supercritical conditions the solvation
properties of liquids change radically: organic molecules
are readily dissolved in aqueous solutions; ionic species
are precipitated due to ion-pairing or clustering effects.
The generated structural modifications must be
accurately described at different scales: density and
compressibility evolution, clustering process or changes
of the local ordering between or within molecules.
Recently, we focused on supercritical water and aqueous
solutions,
using
complementary
spectroscopic
techniques: XAS, IXS and SAXS. XAS and IXS studies
allowed us to establish the molecular structure of
hydration of ions and molecules in water and the unique
structure of hydrogen bonding in pure supercritical
water. In the mesoscopic range, the determination of
inhomogeneous distribution of water molecules in the
compressible regime has been determined by SAXS. The
evolution of hydrogen bonding in water in relation with
permittivity of the solvent from ambient to supercritical
conditions has been shown: under supercritical
conditions, high density clusters of hydrogen bonded
water molecules are surrounded by a low density (gaslike) medium.
Fluid-Rocks interactions
J. James-Smith, J-L. Hazemann, D. Testemale
This study concerns hydrothermal geochemistry, and in
particular the transport of metals and the formation
/dissolution of crustal minerals in hydrothermal fluids.
The key point is the determination of the metal
speciation using EXAFS and ab initio XANES
calculations. There are two main axes of investigation:
-Autoclave experiments: studying the metal speciation
and mineral solubility under controlled T, P and salinity
conditions. Recent examples are the study of speciation
up to 500 bar and 500°C of Cu+, Fe2+ or Ga3+ xx, the
solubility of nantokite and of siderite in sub-surface
conditionsxxi.
-Fluid inclusions experiments: in the context of the
micro-beam spectroscopy development on the CRG
FAME beamline, the speciation of As in natural fluid
inclusions of 50 µm has been determined by EXAFSxxii.
A strong collaboration exists on these topics with
Adelaide University (Australia) G2R (CNRS, Nancy
France) and LMTG (CNRS, Toulouse, France).
Cultural Heritage Materials
M. Anne, D. Bhange, C. Dejoie, E. Dooryhée, P.
Martinetto
The analysis of archaeological objects aims to better
understand the techniques of the ancient cultures and to
preserve the cultural heritage for future generations. This
implies using appropriate tools for examining fragile,
valuable and/or unique artefacts. XPD, supplemented by
spectroscopic and microscopic methods, is a relevant
Institut Néel
crystallographic technique to characterize such materials:
phase identification, quantitative and microstructural
analysis, structure determination… Two examples
involving archaeo-analogues compounds are cited.
In the first, the average microstructure of hydrocerussite
has been identified in Greco-roman white eye makeups,
using high-resolution XPD data. The microstructural
parameters were used as fingerprints and compared with
the values of artificially synthesized 2PbCO3, Pb(OH)2
samples. This allowed the interpretation of the
manufacturing procedures applied by ancient Greeks to
produce eye makeups based on lead white powders.
Reflectance and fluorescence spectra for Maya blue and
the synthetic homologue indigo@silicalite
The
second
example
concerns
the
"Maya
Blue" pigment (ca. 800 A.C.) which is one of the most
ancient organic-inorganic hybrids. The bonding and
sitting of the organic molecule are examined in simpler
parent structures, by inserting organic colouring agents
(e.g. indigo) inside the cages and channels of appropriate
zeolites. The synthetic pigments are characterized by
fluorescence, UV-Vis absorption, Raman spectroscopy,
and X-ray diffraction. In some indigo@zeolite
complexes, we show the poly/mono-merisation of the
organic molecule at the surface and/or in the bulk of the
substrate, depending on microstructure and synthesis
conditions.
Principal references
[1] J. Linol J. et al., Cryst. Growth and Design, (2007)
[2] P. Martinetto et al., J. Phys. Chem. B, (2006)
[3] P. Bleuet et al., Nature Materials (2008)
[4] N. Lemee et al. Physical Review B78 (2008)
[5] P. H. L. Sit et al., Phys. Rev. B (2007)
[6] A. Gianoncelli et al., X-ray spectrometry (2008)
[7] J-L. Hodeau et al.,WO2008/125450Int.Patent (2008)
[8] P. Bordet et al., J. Phys.: Cond. Matt. (2006)
[9] K. Marty et al., Phys. Rev. Lett. (2008)
[10] S. de Brion et al., Phys. Rev. B (2007)
[11] xi H. Muguerra et al., J. Solid State Chem. (2008)
[12] P. Strobel et al., J. Solid State Chem. (2009)
[13] S.R. Oliveira Neto et al. J. of M. M. M. (2008)
[14] S. Zouari et al., Mater. Lett. (2008)
[15] C. Darie et al., Solid State Sciences (2009)
[16] H. Mayot et al., J. Phys. Condens. Matter (2008)
[17] O. Isnard et al., J. Optoelect. and Adv. Mat. (2008)
[18] G. Garbarino et al., Phys. Rev. B (2008)
[19] G. Garbarino et al., Europhys. Lett. (2009)
[20] C. Da Silva et al., J. Mol. Liq. (2008)
[21] D. Testemale et al., Chem. Geol., accepted (2009)
[22] J. James-Smith et al., J. of Geochem. Explor.,(2008)
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