Anisotropic phase diagram and strong coupling effects in Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2}.
We present a thermodynamic study of the phase diagram of single-crystal Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} using specific-heat measurements. In zero-magnetic field a clear step in the heat capacity of {Delta}C/T{sub c} = 0.1 J/mol K{sup 2} is observed at T{sub c} {approx} 34.6 K for a sample with x = 0.4. This material is characterized by extraordinarily high slopes of the upper critical field of {mu}{sub 0}{partial_derivative}H{sub c2}{sup e}/{partial_derivative}T = -6.5 T/K and {mu}{sub 0}{partial_derivative}H{sub c2}{sup ab}/{partial_derivative}T = -17.4 T/K and a surprisingly low anisotropy of {Lambda} {approx} 2.6 near T{sub c}. A consequence of the large field scale is the effective suppression of superconducting fluctuations. Using thermodynamic relations we determine Ginzburg-Landau parameters of {kappa}{sub c} {approx} 100 and {kappa}{sub ab} {approx} 260 identifying Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} as extreme type II. The large value of the normalized discontinuity of the slopes of the specific heat at T{sub c}, (T{sub c}/{Delta}C){Delta}(dC/dT){sub T{sub c}}, {approx}6, indicates strong-coupling effects in Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2}.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC; National Science of Foundation of China; Ministry of Science and Technology of China; Chinese Academy of Science
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 958539
- Report Number(s):
- ANL/MSD/JA-63280
- Journal Information:
- Phys. Rev. B, Journal Name: Phys. Rev. B Journal Issue: 2009 Vol. 79; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
Specific heat and phase diagrams of single crystal iron pnictide superconductors.
Calorimetric determination of the upper critical fields and anisotropy of NdFeAsO{sub 1-x}F{sub x} single crystals.
Effects of Pr ion on the superconducting properties in Y{sub 1{minus}x}Pr{sub x}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystals
Journal Article
·
Sat Feb 28 23:00:00 EST 2009
· Physica C
·
OSTI ID:1006267
Calorimetric determination of the upper critical fields and anisotropy of NdFeAsO{sub 1-x}F{sub x} single crystals.
Journal Article
·
Mon Dec 31 23:00:00 EST 2007
· Phys. Rev. B
·
OSTI ID:947537
Effects of Pr ion on the superconducting properties in Y{sub 1{minus}x}Pr{sub x}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystals
Journal Article
·
Wed Oct 01 00:00:00 EDT 1997
· Physical Review, B: Condensed Matter
·
OSTI ID:632620