The crystal structure of RESr2GaCu2O7

Roth, Georg; Adelmann, P.; Heger, G.; Knitter, Regina; Wolf, Th.

doi:10.1051/jp1:1991165

Cited by 51 publications

(31 citation statements)

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“…The M-1212 structure tolerates a wide range of single-element constituents such as Cu, Co, Fe, Nb, Ta, Ru, Hg, Tl, Al, Ga, and various cation mixtures as M. [4][5][6][7][8] Some of the M-1212 phases are well-established superconductors ͑viz., Cu-1212͒, whereas some of them are nonsuperconducting yet ͑viz., Nb/Al-1212͒. The M-1212 phases with M = Ga, Al, and Co, particularly, have attracted considerable interest as potential superconducting candidates due to the complicated structure of their MO 1Ϯ␦ charge reservoirs.…”

Section: Introductionmentioning

confidence: 99%

“…The M-1212 phases with M = Ga, Al, and Co, particularly, have attracted considerable interest as potential superconducting candidates due to the complicated structure of their MO 1Ϯ␦ charge reservoirs. [4][5][6][7][8] In the charge reservoir, the M cations are tetrahedrally coordinated by oxygen atoms to form chains of corner-sharing MO 4 tetrahedra that run diagonally relative to the perovskite base. Further, it has been reported that the MO 4 tetrahedra are arranged into two kinds of chain, L ͑left͒ and R ͑right͒ in which the tetrahedra rotate in different ways.…”

Section: Introductionmentioning

confidence: 99%

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Structural and magnetic properties of Co1−xFexSr2YCu2O7+δ compounds

Singh

Kumar

Husain

et al. 2010

Journal of Applied Physics

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Here we study the structural and magnetic properties of the Co1−xFexSr2YCu2O7+δ compound (0≤x≤1). X-ray diffraction patterns and simulated data obtained from Rietveld refinement of the same indicate that the iron ion replacement in Co1−xFexSr2YCu2O7+δ induces a change in crystal structure. The orthorhombic Ima2 space group structure of Co-1212 changes to tetragonal P4/mmm with increasing Fe (x≥0.5) ion. The XPS studies reveal that both Co and Fe ions are in mixed states of 3+/4+ for the former and 2+/3+ in case of later. The magnetization with temperature follows Curie–Weiss behavior, in the range of 150–300 K and short magnetic correlations/spin glasslike features below 150 K. The observed magnetic behavior is due to competition of antiferro/ferromagnetic exchange interaction of Co3+ [intermediate spin (IS)]-O–Co3+ (IS)/Co4+ [low spin (LS)] and Fe3+ [high spin (HS)]-O–Fe2+ (LS)/Fe3+ (HS)/Co3+ (IS)/Co4+ (LS) states. Although none of the studied as synthesized samples in Co1−xFexSr2YCu2O7+δ are superconducting, the interesting structural changes in terms of their crystallization space groups and the weak magnetism highlights the rich solid state chemistry of this class of materials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structural and magnetic properties of Co1−xFexSr2YCu2O7+δ compounds

Singh

Kumar

Husain

et al. 2010

Journal of Applied Physics

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“…Sample purity before and after measurement was confirmed using X-ray diffraction. [3][4][5]. In the case of YSr 2 Cu 2 CoO 7+y , no measureable oxygen loss was observed in air or N 2 between 25 and 900ºC.…”

Section: Introductionmentioning

confidence: 88%

“…However, the results showed that the material experienced a number of problems. At raised temperatures (>900 o C) there was significant degradation of the structure including 4 decomposition and a reaction with YSZ. There was also electrochemical decomposition at fairly low current densities (20 mAcm -2 ) [1].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and characterisation of the perovskite-related cuprate phases YSr2Cu2MO7+y(M = Co, Fe) for potential use as solid oxide fuel cell cathode materials

et al. 2005

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In this paper we report the synthesis and characterisation of the perovskite cuprate phases YSr 2 Cu 2 MO 7+y (M=Co, Fe) to examine their potential for use as cathode materials in Solid Oxide Fuel Cells (SOFC). Both samples showed conductivities of ≈10 Scm -1 at 900°C and were also shown to be stable at this temperature in N 2 . For YSr 2 Cu 2 FeO 7+x , semiconducting behaviour was observed up to ≈550°C, with a decrease in conductivity at higher temperatures, attributed to oxygen loss reducing the charge carrier concentration.In the case of YSr 2 Cu 2 CoO 7+y , semiconducting behaviour was observed over the range of temperatures studied, although a small but significant steep increase in conductivity was observed above 800°C. High temperature X-ray diffraction studies of this particular phase showed that this increase in conductivity coincided with an orthorhombictetragonal structural transition, accompanied by a significant reduction in cell volume. In addition to measurements in air, conductivities were also measured with varying p(O 2 ) (0.2-10 -5 atm.) at 900°C, and this data showed significant hysteresis between measurements on reducing and re-oxidising, suggesting poor oxide ion transport, poor oxygen surface exchange kinetics, or significant structural changes on varying p(O 2 ).Chemical compatibility studies of these phases with SOFC electrolytes at temperatures between 900 and 1000°C showed reaction in all cases. In the case of CeO 2 based electrolytes, the reaction led to the formation of the "fluorite-block" phases, (Y/Ce) 2 Sr 2 Cu 3-x M x O 9+y (M=Co, Fe), and samples of these were subsequently prepared and the conductivities measured. Similar hysteresis between conductivity measurements on reducing and re-oxidising were also observed for these samples.

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Structural studies on Superconducting materials and fullerites by electron microscopy

Tendeloo

Amelinckx

1993

Advanced Materials

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High‐resolution electron microscopy (HREM) has proved invaluable in the study of local structure—i.e. defects—which in many cases govern the physical, chemical, and electrical properties of materials. The use of HREM in investigations of cuprate high‐temperature superconductors is reviewed, especially for compounds in which substituents replace some of the copper. HREM can also be very successfully combined with other techniques, such as electron diffraction, as is demonstrated by results of research on the structure and phase transitions of C60 and C70.

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The crystal structure of RESr₂GaCu₂O₇

Cited by 51 publications

References 0 publications

Structural and magnetic properties of Co1−xFexSr2YCu2O7+δ compounds

Structural and magnetic properties of Co1−xFexSr2YCu2O7+δ compounds

Synthesis and characterisation of the perovskite-related cuprate phases YSr2Cu2MO7+y(M = Co, Fe) for potential use as solid oxide fuel cell cathode materials

Structural studies on Superconducting materials and fullerites by electron microscopy

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