44 research outputs found
Nanoscale textured superconductivity in Ru-substituted BaFe2As2 : a challenge to a universal phase diagram for the pnictides
75As NMR experiments were performed in Ba(Fe1-xRux)2As2 for x=0 to 80%.
Magnetic fractions and NMR lineshapes demonstrate that Ru substitution destroys
the antiferromagnetic (AF) order inhomogeneously with a magnetic moment
distributed from 0.9 to 0 uB. Superconductivity emerges at intermediate Ru
doping and coexists with AF order only in the regions where moments are smaller
than ~0.3uB, resulting in an original nanoscale texture. This situation
contrasts with that of Co substitution, challenging the apparent universality
of the phase diagram in Fe-based superconductors
Structure de La6Cu2Si2S14
Collin Gaston, Laruelle Pierre. Structure de La6Cu2Si2S14. In: Bulletin de la Société française de Minéralogie et de Cristallographie, volume 94, 2, 1971. pp. 175-176
Structure cristalline du sulfure La2Fe2S5
Description of the structure of orthorhombic LaâFeâSâ
of space group A2âam with parameters :
a = 11.40 Ă
, b = 16.55 Ă
, c = 4.055 Ă
(ZÂ =Â 4).
The rare earth atoms occupy two equivalent sites of coordination number 7, while the iron atoms are distributed between two very different types of sites : one associated with a deformed octahedral structure and the other with a tetragonal structure. The final factor R is 0.068.Description de la structure de LaâFeâSâ
orthorhombique du groupe spatial A2âam dont les paramĂštres sont :
a = 11,40 Ă
, b = 16,55 Ă
, c = 4,055 Ă
(ZÂ =Â 4).
Les atomes de terres rares occupent deux sites sensiblement équivalents de coordinence 7, alors que les atomes de fer sont répartis dans deux types de sites trÚs différents : l'un octaédrique déformé et le second tétraédrique. Le facteur R final est de 0,068.Collin Gaston, Laruelle Pierre. Structure cristalline du sulfure La2Fe2S5. In: Bulletin de la Société française de Minéralogie et de Cristallographie, volume 94, 2, 1971. pp. 113-117
Landolt-Börstein. Numerical data and functionnal relationships in science and technology, 1971
Ătienne J.-J., Collin Gaston. Landolt-Börstein. Numerical data and functionnal relationships in science and technology, 1971. In: Bulletin de la SociĂ©tĂ© française de MinĂ©ralogie et de Cristallographie, volume 95, 1, 1972. RĂ©union annuelle de l'Association Française de Cristallographie, Lille, 6-8 mai 1971
Landolt-Börstein. Numerical data and functionnal relationships in science and technology, 1971
Ătienne J.-J., Collin Gaston. Landolt-Börstein. Numerical data and functionnal relationships in science and technology, 1971. In: Bulletin de la SociĂ©tĂ© française de MinĂ©ralogie et de Cristallographie, volume 95, 1, 1972. RĂ©union annuelle de l'Association Française de Cristallographie, Lille, 6-8 mai 1971
Composés hexagonaux L6B2C2X14 lacunaires ordonnés
Several series of compounds Lâ(Bâââ ââ) CâXââ have been prepared. Ordering in vacancies appears only when the vacancy-cation ratio on the B site is greater than one. The superstructure unitcell parameters are aââ3 and 2 câ for Lâ (Bâ/â ââ/â) CâXââ compounds, aââ3 and 3 câ for Lâ (Bâ/â ââ/â) CâXââ. The distribution of vacancies and cations are given for both superstructure patterns.Plusieurs sĂ©ries de composĂ©s Lâ(Bâââ ââ) CâXââ sont prĂ©parĂ©es. La mise en ordre des lacunes apparaĂźt quand le rapport lacune sur cation sur le site B est supĂ©rieur Ă 1. Les mailles de sur-structure ont pour paramĂštres aââ3 et 2 câ pour les composĂ©s Lâ (Bâ/â ââ/â) CâXââ, aââ3 et 3 câ pour les composĂ©s Lâ (Bâ/â ââ/â) CâXââ. Les rĂ©partitions des lacunes et des cations sur les sites B sont dĂ©terminĂ©es pour les deux types de sur-structure.Collin Gaston, Etienne Jean, Laruelle Pierre. ComposĂ©s hexagonaux L6B2C2X14 lacunaires ordonnĂ©s. In: Bulletin de la SociĂ©tĂ© française de MinĂ©ralogie et de Cristallographie, volume 96, 1, 1973. pp. 12-17
DĂ©fauts planaires et nonËstĆchiomĂ©trie dans les composĂ©s NiAs lacunaires
The two compounds FeâSâ (2a2a3c) and Niâ.ââS are studied using the Cowley's theory. It is shown that they are both characterized on one hand : by microtwins due to planar defects interchanging along câ the M and S chains and one calculates the fault rates α, and on the other hand : by imbricated sequences with different types either 3c â 4c in FeâSâ at constant stoichiometry, or 3a3a3c â 2a2a3c in Niâ.ââS with different stoichiometries.On Ă©tudie Ă l'aide de la thĂ©orie de Cowley les deux composĂ©s FeâSâ (2a2a3c) et Niâ,ââS. On montre qu'ils sont tous deux caractĂ©risĂ©s par : d'une part des micromacles dues Ă des dĂ©fauts planaires interchangeant selon câ les chaĂźnes M et S et on calcule les taux de fautes α, et d'autre part par des sĂ©quences imbriquĂ©es de types diffĂ©rents, soit 3c â 4c dans FeâSâ Ă stĆchiomĂ©trie constante, soit 3a3a3c â 2a2a3c dans Niâ,ââS avec des stĆchiomĂ©tries diffĂ©rentes.Collin Gaston, Chavant Chistiane, Keller-Besrest Françoise. DĂ©fauts planaires et nonËstĆchiomĂ©trie dans les composĂ©s NiAs lacunaires. In: Bulletin de MinĂ©ralogie, volume 103, 3-4, 1980. PropriĂ©tĂ©s des solides minĂ©raux. I. Dissolution. II. Ordre-dĂ©sordre
Sr
We show that, contrary to previous belief, the transition to the antiferromagnetic state of Sr2IrO4 in zero magnetic field does show up in the transverse resistivity. We attribute this to a change in transverse integrals associated to the magnetic ordering, which is evaluated considering hopping of the localized charge. The evolution of the resistivity anomaly associated to the magnetic transition under applied magnetic field is studied. It tracks the magnetic phase diagram, allowing to identify three different lines, notably the spin-flip line, associated with the reordering of the ferromagnetic component of the magnetization, and an intriguing line for field induced magnetism, also corroborated by magnetization measurements