Low-temperature specific heat of several high-temperature superconductors in the superconducting and mixed states

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:6464122

Stupp, S E

The low-temperature specific heat of high quality, well characterized sintered polycrystalline samples of superconducting Ba(0.6)K(0.4)BiO(3), YBa(2)Cu(3)O(6.7), and Bi(2)Sr(2)CaCu(2)O(8+x) were measured in the superconducting state. Careful analysis of the data below 10 K indicate that the contribution to the specific heat which has a linear dependence on temperature, which has been observed in samples of YBa(2)Cu(3)O(7-delta), is not a universal feature of the high temperature superconductors. It was observed that the linear term in YBa(2)Cu(3)O(7-delta) is weakly dependent on the oxygen content, delta. The authors argue that a linear term of 4 mJ/mole K2 is intrinsic to this compound, and while the origin of this linear term is still unknown it does not appear to be associated with the superconducting state. The low-temperature specific heat of the Bi(2)Sr(2)CaCu(2)O(8+x) samples were also measured in the mixed state in applied magnetic fields up to 3T. A strong field dependence in the specific heat was observed in the YBa(2)Cu(3)O(6.7) sample, while the specific heat of Bi(2)Sr(2)CaCu(2)O(8+x) was independent of field. The presence of a large field dependence at low-temperatures in the mixed state is not in agreement with the predictions of London theory. The authors mention several possible explanations for the large field dependence of the specific heat, including novel vortex structures, vortex kink nucleation, vortex core interactions, proximity effect coupling, and nodes in the superconducting gap.

• Research Organization: Illinois Univ., Urbana, IL (United States)
• OSTI ID: 6464122
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
HIGH-TC SUPERCONDUCTORS
MAGNETIC FIELDS
MIXED STATE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLYCRYSTALS
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
SPECIFIC HEAT
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES