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Alla Arakcheeva

Cette personne a quitté l’EPFL

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Publications associées (42)

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Crystal Structure, Transport, and Magnetic Properties of an Ir6+ Compound Ba8Al2IrO14

László Forró, Henrik Moodysson Rønnow, Arnaud Magrez, Alla Arakcheeva, Krunoslav Prsa, Andrea Pisoni, Ana Akrap, Jacim Jacimovic, Sergiy Katrych, Lin Yang, Bastien Dalla Piazza

The novel iridate Ba8Al2IrO14 was prepared as single crystals by self-flux method, thereby providing a rare example of an all-Ir(VI) compound that can be synthesized under ambient pressure conditions. The preparation of all-Ir6+ iridate without using tradi ...

2015

Validating the model of a (3+1)-dimensional incommensurately modulated structure as generator of a family of compounds for the Eu2(MoO4)3 scheelite structure

Gervais Chapuis, Philip Pattison, Alla Arakcheeva

The previously proposed model postulating that the incommensurately modulated KNd(MoO

_4

)

_2

structure can act as a generator of the scheelite family members is validated here by refining the crystal structure of europium molybdate, Eu

_2

(MoO

_4

)

_3

. ...

2009

Atomic clusters and phase transitions in the metastable beta-Ta phase between 4.2 and 293 K

Gervais Chapuis, Alla Arakcheeva

Atomic clusters were identified in the ground state of the non-equilibrium Ta phase (Frank-Kasper sigma-structure type) at 15, 120 and 293K. The evolution of the clusters with temperature leads to two phase transformations at 65 and 150K which are related ...

IOP Publishing - EPL Association2005

Possibility of an unconventional spin state of Ir4+ in Ba21Ir9O43 single crystal

László Forró, Henrik Moodysson Rønnow, Oleg Yazyev, Arnaud Magrez, Bálint Náfrádi, Ivica Zivkovic, Alla Arakcheeva, Lin Yang, Andrea Pisoni, Sergiy Katrych, Jacim Jacimovic, Noore Elahi Shaik

We report the synthesis of single crystals of a novel layered iridate Ba21Ir9O43 and present the crystallographic, transport, and magnetic properties of this material. The compound has a hexagonal structure with two iridium oxide layers stacked along the c ...

Amer Physical Soc2016

The influence of the incommensurately modulated structure on the physical properties of Fe1.35Ge

László Forró, Helmuth Berger, Philip Pattison, Alla Arakcheeva, Jacim Jacimovic, Sergiy Katrych, Andrea Pisoni, Krunoslav Prsa

Single crystal growth by chemical vapour transport has resulted samples with Fe1.35Ge stoichiometry. Structural study has shown that the large number of vacancies introduces an incommensuately modulated structure. The electrical resistivity is in the 200 m ...

2019

Application of micro X-ray diffraction to investigate the reaction products formed by the alkali–silica reaction in concrete structures

Gervais Chapuis, Philip Pattison, Alla Arakcheeva

Alkali-silica reaction (ASR) is one of the most important deterioration mechanisms in concrete leading to substantial damages of structures worldwide. Synchrotron-based micro-X-ray diffraction (micro-XRD) was employed to characterize the mineral phases for ...

Pergamon-Elsevier Science Ltd2016

Incommensurate crystal structure of PbHfO3

Alla Arakcheeva

Controversy in the description/identification of so-called intermediate phase(s) in PbHfO3, stable in the range similar to 420-480 K, has existed for a few decades. A synchrotron diffraction experiment on a partially detwinned crystal allowed the structure ...

INT UNION CRYSTALLOGRAPHY2020

Na2/7Gd4/7MoO4: a Modulated Scheelite-Type Structure and Conductivity Properties

Alla Arakcheeva

Scheelite-type compounds with the general formula (A1,A2)(n)(B1,B2)O-4 (2/3

2012

Cyan titania nanowires: Spectroscopic study of the origin of the self-doping enhanced photocatalytic activity

László Forró, Arnaud Magrez, Bálint Náfrádi, Endre Horvath, Richard Gaal, Alla Arakcheeva, Massimo Spina, Jacim Jacimovic, Péter Szirmai, Laurent Syavoch Bernard

We report a detailed spectroscopic study of Ti3+ self-doped TiO2 nanowires prepared by high temperature annealing of the protonated titanate nanowires (TiONW) in hydrogen atmosphere. Hydrogenation causes a color change from white to cyan and a major increa ...

Elsevier2017

The role of silver on the stabilization of the incommensurately modulated structure in calaverite, AuTe2

Gervais Chapuis, Alla Arakcheeva

Structural investigations of several minerals belonging to the calaverite group with composition Au1–xAgxTe2 (x = 0.00, 0.02, 0.05, 0.09, 0.19, and 0.33) indicate that Ag is randomly distributed on the Au sites. This suppresses the valence fluctuation of A ...

Mineralogical Society of America2009

Synthesis, growth and characterization of 4-bromo-4′-nitrobenzylidene aniline (BNBA): a novel nonlinear optical material with a (3+1)-dimensional incommensurately modulated structure

Gervais Chapuis, Philip Pattison, Alla Arakcheeva

The organic nonlinear optical material of 4-bromo-4'-nitrobenzylidene aniline (BNBA, C13H9BrN2O2), a new derivative of benzylideneaniline family, was synthesized and purified by repeated recrystallization. Single crystals of BNBA were grown in acetone solv ...

Royal Society of Chemistry2013

The luminescence of NaxEu3+(2−x)/3MoO4 scheelites depends on the number of Eu-clusters occurring in their incommensurately modulated structure

Gervais Chapuis, Jean-Claude Bünzli, Philip Pattison, Alla Arakcheeva, Svetlana Eliseeva

Scheelite related compounds with general formula Mn(XO4)m are of interest owing to their optical properties, stability and relatively simple preparation. Eu3+-containing scheelites are considered as red emitting phosphors and the main factors affecting the ...

2012

The importance of characterizing incommensurately modulated structures for the study of physical properties

Alla Arakcheeva

INT UNION CRYSTALLOGRAPHY2022

Organic-inorganic hybrid perovskite CH3NH3PbI3: structural consequences of water absorption

László Forró, Endre Horvath, Alla Arakcheeva, Massimo Spina

IUCr/Wiley2016

Incommensurate atomic density waves in the high-pressure IVb phase of barium

Gervais Chapuis, Philip Pattison, Alla Arakcheeva

The host–guest structures of elements at high pressure discovered a decade ago still leave many open questions due to the lack of precise models based on full exploitation of the diffraction data. This concerns in particular Ba IV, which is stable in the r ...

Int Union Crystallography2017

Electronic properties of incommensurately modulated novel and complex materials

László Forró, Oleg Yazyev, Philip Johannes Walter Moll, Alla Arakcheeva, Ana Akrap, Sergiy Katrych, Gabriel Albert Autes, Edoardo Martino

INT UNION CRYSTALLOGRAPHY2018

A reinterpretation of the phase transitions in Na2CO3

Gervais Chapuis, Alla Arakcheeva

Based on the structural data of phases alpha (hexagonal; 756-972 K), beta (monoclinic; 605-751 K), gamma (incommensurate, monoclinic; 295 K) and delta (lock-in, monoclinic; 110 K) of sodium carbonate, Na2CO3, we could draw a parallel between the phase tran ...

2005

KNd(MoO4)2: A New Incommensurate Modulated Structure in the Scheelite Family

Gervais Chapuis, Alla Arakcheeva

2006

Getting more out of an incommensurately modulated structure: the example of K_5Yb(MoO_4)_4

Gervais Chapuis, Alla Arakcheeva

A method based on the superspace approach is presented with the aim of generating a family of modular structures from a single incommensurately modulated structure. This approach based on the variation of the modulation vector q is applied to the generatio ...

2006

Capabilities and limitations of a (3 + d )-dimensional incommensurately modulated structure as a model for the derivation of an extended family of compounds: example of the scheelite-like structures

Gervais Chapuis, Alla Arakcheeva

2008