0000000000160697

AUTHOR

R. Jakobi

showing 4 related works from this author

Thermodynamics of the spin transition in [FexZn1−x(2-pic)3]Cl2 · EtOH

1992

Abstract With a new type of calorimeter we reinvestigated the specific heat Cp of the mixed crystals [FexZni1−x(2-pic)3]Cl2 · EtOH in the temperature range from 15 to 300 K. On the basis of a phenomenological thermodynamic model the anomaly in the Cp(T) curve of the mixed crystal (x = 0.73) can be quantitatively described as a result of the spin transition (1A1(low spin, LS) → 5T2(high spin, HS)). The parameters of the Gibbs free energy were independently derived from the temperature dependence of the HS fraction γ in [FexZn1−x(2-pic)3]Cl2 · EtOH. The pure iron complex (x = 1) exhibits a two-step spin transition. In the temperature range between the two steps the entropy obtained from the C…

ChemistrySpin transitionThermodynamicsGeneral ChemistryCalorimetryAtmospheric temperature rangeCondensed Matter PhysicsMagnetic susceptibilityGibbs free energyCrystalsymbols.namesakePhenomenological modelsymbolsPhysical chemistryMoleculeGeneral Materials ScienceJournal of Physics and Chemistry of Solids
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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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Nature of the phase transition in spin crossover compounds

1990

Abstract Starting from the phenomenological free energy describing the spin equilibrium of continuous or gradual high spin (HS) ⇌ low spin (LS) transitions a reduced equation of state has been derived which is of the type known in mean field theories. The continuous HS ⇌ LS transitions of [Fe(2-pic-ND 2 ) 3 ]Cl 2 ·EtOD (2-pic = 2-picolylamine) at ambient pressure and p = 1200 bar and of [Fe(2-pic) 3 ]Cl 2 -MeOH can be classified as isobars above the critical point of the system. Around and below the critical point a complex behaviour is expected for thermodynamic reasons combined with the consequences of an elastic interaction mechanism between the HS and LS complex molecules in the crystal…

Phase transitionChemistryHydrostatic pressureThermodynamicsGeneral ChemistryCondensed Matter PhysicsNuclear magnetic resonanceMean field theoryCritical point (thermodynamics)Spin crossoverIsobarSpin density waveGeneral Materials ScienceSolid solutionJournal of Physics and Chemistry of Solids
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ChemInform Abstract: Thermoanalytic Investigations on Mixed Crystals of the Spin-Crossover System (FexZn1-x(2-pic-ND2)3)Cl2·EtOD

1988

ChemistrySpin crossoverInorganic chemistryPhysical chemistryGeneral MedicineChemInform
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