Ferroelectrics · 1989 · 16 citations · 4 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsHeat TransferSolid State PhysicsHeat ConductionHeat Transfer In SolidsSinteringSuperconducting MaterialsThermal Properties Of CeramicsThermal Properties Of MaterialsAnisotropic Thermal BehaviorAnisotropic Thermal ConductivityHeat Conduction In SolidsHeat Transfer CharacterizationHeat Transfer MechanismsSuperconducting CeramicsTemperature Dependence Of Thermal ConductivityThermal Conductivity
Abstract We report measurements of the thermal conductivity k on hot-pressed sintered Y Ba2Cu3O7-δ samples over a wide temperature range, 0.055 < T < 300 K. Depending on the direction of heat transfer with respect to the direction the samples were hot-pressed, the thermal conductivity displayed noticeable anisotropic behavior at high temperatures, T > 50 K, and at very low temperatures, T < 0.2 K. This behavior is interpreted as evidence that hot-pressing promotes partial orientation effects of the crystallites and that measurements of k are sensitive to these effects. At T > 100 K the behavior of k is nearly constant with temperature up to 270 K, while at low temperatures (T < 0.2 K) k departs from a T 3 dependence and either becomes linear in T when the heat current is parallel to the pressing direction or it becomes quadratic, i.e. T 2 dependent when the heat current is perpendicular to the press direction.
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