Heat capacity of superconducting Ba0.6K0.4BiO3 near Tc

J. E. Graebner, L. F. Schneemeyer, J. K. Thomas

Research output: Contribution to journalArticle

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Abstract

Measurements of the heat capacity of single crystals of Ba0.6K0.4 BiO3 in the range 1040 K and in magnetic fields up to 60 kOe reveals a jump at Tc. The phase diagram of Hc2(T) can thus be determined calorimetrically, yielding values of Tc(H=0)=31.5 K and dHc2/dT=-5.2 kOe/K, in agreement with recent magnetization measurements. From these data, and the value of dHc1/dT from magnetization data, the size of the jump is consistent with at least 40% of the sample volume becoming a superconductor, indicating that superconductivity in this material is a bulk property and not due to a trace amount of a second phase. The corresponding value of the electronic specific-heat coefficient is =1.5 mJ/mol K2. Comparison with the band-structure density of states yields a value of the electron-phonon coupling constant of 0.35, consistent with the assumption that the material is a weakly coupled superconductor.

Original languageEnglish
Pages (from-to)9682-9684
Number of pages3
JournalPhysical Review B
Volume39
Issue number13
DOIs
StatePublished - 1 Jan 1989

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Superconducting materials
Specific heat
Magnetization
specific heat
magnetization
Superconductivity
Band structure
Phase diagrams
superconductivity
phase diagrams
Single crystals
Magnetic fields
Electrons
single crystals
coefficients
electronics
magnetic fields
electrons

Cite this

Graebner, J. E. ; Schneemeyer, L. F. ; Thomas, J. K. / Heat capacity of superconducting Ba0.6K0.4BiO3 near Tc. In: Physical Review B. 1989 ; Vol. 39, No. 13. pp. 9682-9684.
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Heat capacity of superconducting Ba0.6K0.4BiO3 near Tc. / Graebner, J. E.; Schneemeyer, L. F.; Thomas, J. K.

In: Physical Review B, Vol. 39, No. 13, 01.01.1989, p. 9682-9684.

Research output: Contribution to journalArticle

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AB - Measurements of the heat capacity of single crystals of Ba0.6K0.4 BiO3 in the range 1040 K and in magnetic fields up to 60 kOe reveals a jump at Tc. The phase diagram of Hc2(T) can thus be determined calorimetrically, yielding values of Tc(H=0)=31.5 K and dHc2/dT=-5.2 kOe/K, in agreement with recent magnetization measurements. From these data, and the value of dHc1/dT from magnetization data, the size of the jump is consistent with at least 40% of the sample volume becoming a superconductor, indicating that superconductivity in this material is a bulk property and not due to a trace amount of a second phase. The corresponding value of the electronic specific-heat coefficient is =1.5 mJ/mol K2. Comparison with the band-structure density of states yields a value of the electron-phonon coupling constant of 0.35, consistent with the assumption that the material is a weakly coupled superconductor.

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