9 / 33
Page 34
Notes:
conferenceseries
.com
Volume 3, Issue 2
ISSN: 2470-9905
Crystallography 2017
October 16-17, 2017
2
nd
International Conference on
October 16-17, 2017 | Chicago, USA
Applied Crystallography
Interplay between H-bonding and charge ordering in Fe
3
(PO
4
)
2
(OH)
2
barbosalite
J Rouquette
1
, J Haines
1
, V Ranieri
1
, M Poienar
2
, A Guesdon
3
and
C Martin
3
1
Université Montpellier, France
2
CRISMAT, France
3
Laboratoire Léon Brillouin, France
C
harge Ordering (CO) in transition metal oxides is an important parameter for obtaining original magnetic and/or electric
properties. That was largely shown within the framework of the studies on colossal magneto-resistance in manganese perovskites
and it again seems to be at the origin of the ferroelectricity in CaMn
7
O
12
or LuFe
2
O
4
. The mixed valence of iron in the system is a
particularmotivation in viewof the long lasting research on the understanding of the effects of pressure on charge order/magnetic order
in iron compounds such as the LuFe
2
O
4
new charge ordered state and the pressure dependence of its magnetic order. Here we focus
on Fe
2+
Fe
3+
2
(PO
4
)
2
(OH)
2
barbosalite single crystal, an hydroxyphosphate of iron which exhibits a mixed valence state. High pressure
behavior of barbosalite was successfully characterized based on single crystal X-ray diffraction, Raman and infrared spectroscopies.
Fe
2+
Fe
3+
2
(PO
4
)
2
(OH)
2
presents two phase transition at close to 3 and 8 GPa respectively which are clearly governed by an interplay
between H-bonding and electron delocalization. Moreover the temperature reaction Fe
2+
Fe
3+
2
(PO
4
)
2
(OH)
2+
Fe
3+
3
(PO
4
)
2
(OOH).
Figure 1:
h0l
reconstruction of the reciprocal space of incommensurate Fe
3+
3
(PO
4
)
2
(OOH).
Biography
J Rouquette has obtained his PhD in Julien Haines’ group in Materials Science (Condensed Matter) from University of Montpellier, France in 2004 and was a Postdoctoral
Fellow in Leonid Dubrovinsky’s group at the Bayerisches Geoinstitut in Bayreuth University, Germany for two years. He has joined the CNRS as a Researcher in 2004 in
the field of ferroelectrics/multiferroics and he defended his Habilitation in 2012 entitled “
insitu
structural studies of ferroic materials as a function of P,T,E,B. He has published
more than 50 research papers in these areas.
jerome.rouquette@umontpalllier.frJ Rouquette et al., Struct Chem Crystallogr Commun, 3:2
DOI: 10.21767/2470-9905-C1-002