Small anisotropy, weak thermal fluctuations, and high field superconductivity in Co-doped iron pnictide Ba(Fe1-xCox)2As2

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3081455· OSTI ID:1004949

Yamamoto, A. ^[1]; Jaroszynski, J. ^[1]; Tarantini, C. ^[1]; Balicas, L. ^[1]; Jiang, J. ^[1]; Gurevich, A. ^[1]; Larbalestier, D. C. ^[1]; Jin, Rongying ^[2]; Sefat, A. S. ^[3]; McGuire, Michael A ^[2]; Sales, Brian C ^[2]; Christen, David K ^[2]; Mandrus, David ^[2]

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1. Florida State University
2. ORNL
3. Oak Ridge National Laboratory (ORNL)

We performed high-field magnetotransport and magnetization measurements on a single crystal of the 122-phase iron pnictide Ba(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2}. Unlike the high-temperature superconductor cuprates and 1111-phase oxypnictides, Ba(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} showed practically no broadening of the resistive transitions under magnetic fields up to 45 T. We report the temperature dependencies of the upper critical field H{sub c2} both parallel and perpendicular to the c-axis, the irreversibility field H{sub irr}{sup c}(T), and a rather unusual symmetric volume pinning force curve F{sub p}(H) suggestive of a strong pinning nanostructure. The anisotropy parameter {gamma} = H{sub c2}{sup ab}/H{sub c2}{sup c} deduced from the slopes of dH{sub c2}{sup ab}/dT = 4.9 T/K and dH{sub c2}{sup c}/dT = 2.5 T/K decreases from -2 near T{sub c}, to -1.5 at lower temperatures, much smaller than {gamma} for 1111 pnictides and high-T{sub c} cuprates.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1004949
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 6 Vol. 94; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANISOTROPY
CRITICAL FIELD
CUPRATES
FLUCTUATIONS
IRON
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETIZATION
MONOCRYSTALS
PNICTIDES
SUPERCONDUCTIVITY
SUPERCONDUCTORS