Free energy of thallium-based superconductors

M. M. Fang; J. E. Ostenson; D. K. Finnemore; D. E. Farrell; N. P. Bansal

doi:10.1103/PhysRevB.39.222

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Free energy of thallium-based superconductors

M. M. Fang, J. E. Ostenson, D. K. Finnemore, D. E. Farrell, N. P. Bansal

DOI 10.1103/PhysRevB.39.222 · Physical Review B

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Abstract

Free-energy surfaces have been determined for both Tl2Ba2Ca1Cu2O8 and Tl2Ba2Ca2Cu3O10 in order to determine the thermodynamic aspects of vortex formation in the mixed state of these materials. For fields up to 5 T, the free-energy change, GH−G0, is found to be linear in temperature, over a wide temperature range, thus indicating that the specific heat is roughly independent of magnetic field. The slope of the upper critical field versus temperature plot is at least 20 T/K. These two materials obey a law of corresponding states.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Tl2Ba2CaCu2O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure unresolved	unknown
Tl2Ba2Ca2Cu3O10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	120	Pressure unresolved	onset
YBa2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	92	Pressure not reported	unknown