0000000000416912

AUTHOR

H. Engelmann

showing 2 related works from this author

Structure and superconducting properties of YBa2(Cu1−x Fex)3O7

1988

Fe-substituted Y-Ba-Cu superconducting oxide compounds were investigated by dc-magnetic susceptibility measurements, powder X-ray diffraction and Mdssbauer spectroscopy. Fe substitution caused a structural transformation from orthorhombic to tetragonal. Up to 4 at% Fe Tc was almost unaffected. It was found that superconductivity in Cu oxides does not depend on orthorhombic crystal symmetry.

DiffractionSuperconductivityMaterials scienceCondensed matter physicsOxideEnergy Engineering and Power TechnologyCondensed Matter PhysicsStructural transformationElectronic Optical and Magnetic MaterialsTetragonal crystal systemCrystallographychemistry.chemical_compoundchemistryOrthorhombic crystal systemElectrical and Electronic EngineeringSpectroscopyPhysica C: Superconductivity
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A M�ssbauer and ESR study of LiNbO3-Fe2O3 for low Fe2O3 concentrations

1989

Samples of the system LiNbO3-Fe2O3 prepared by water quenching and by the double-roller quenching method in the range up to 24 mol% Fe2O3 were investigated by Mossbauer and ESR spectroscopy. In the water quenched samples up to 11 mol% Fe2O3 only the Fe3+ and the Fe2+ valence states could be detected. The Fe2+ concentration decreased with increasing Fe2O3 content. Above 11 mol% Fe2O3 magnetically split Mossbauer spectra indicated the presence of Fe2O3 clusters. The isomer shift values of Fe3+ as a function of Fe2O3 concentration showed jumps at 6 and 11 mol% Fe2O3, whereas no significant changes could be detected in the quadrupole splitting values. The ESR data already exhibited the existenc…

inorganic chemicalschemistry.chemical_classificationQuenchingValence (chemistry)Physics and Astronomy (miscellaneous)General EngineeringAnalytical chemistryGeneral ChemistryQuadrupole splittingIonlaw.inventionNuclear magnetic resonancechemistrylawMössbauer spectroscopyGeneral Materials ScienceElectron paramagnetic resonanceSpectroscopyInorganic compoundApplied Physics A Solids and Surfaces
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