Transport and superconducting properties of RNi{sub 2}B{sub 2}C (R=Y, Lu) single crystals

Journal Article · Tue Apr 01 00:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.8506· OSTI ID:537230

Rathnayaka, K D; Bhatnagar, A K; Parasiris, A; Naugle, D G ^[1]; Canfield, P C; Cho, B K ^[2]

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1. Physics Department, Texas AM University, College Station, Texas 77843-4242 (United States)
2. Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)

The in-plane resistivity, in-plane absolute thermopower, and upper critical field measurements are reported for single-crystal samples of YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C superconductors. The in-plane resistivity shows metallic behavior and varies approximately linearly with temperature near room temperature (RT) but shows nearly quadratic behavior in temperature at low temperatures. The YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C single-crystal samples exhibit large transverse magnetoresistance ({approx}6{endash}8{percent} at 45 kOe) in the ab plane. The absolute thermopower S(T) is negative from RT to the superconducting transition temperature T{sub c}. Its magnitude at RT is a few times of the value for a typical good metal. S(T) is approximately linear in temperature between {approx}150 K and RT. Extrapolation to T=0 gives large intercepts (few {mu}V/K) for both samples suggesting the presence of a much larger {open_quotes}knee{close_quotes} than would be expected from electron-phonon interaction renormalization effects. The upper critical fields for H parallel and perpendicular to the c axis and the superconducting parameters derived from it do not show any anisotropy for the YNi{sub 2}B{sub 2}C single-crystal samples in agreement with magnetization and torque magnetometry measurements, but a small anisotropy is observed for the LuNi{sub 2}B{sub 2}C single crystals. The analysis shows that these are moderately strong-coupling type-II superconductors (similar to the A-15 compounds) with a value of the electron-phonon coupling parameter {lambda}(0) approximately equal to 1.2 for YNi{sub 2}B{sub 2}C and 1.0 for LuNi{sub 2}B{sub 2}C, the Ginzburg-Landau coherence length {xi}(0) approximately equal to 70 {Angstrom}, and H{sub c2}(0){approximately}60{endash}70 kOe. (Abstract Truncated)

• OSTI ID: 537230
• Journal Information: Physical Review, B: Condensed Matter, Vol. 55, Issue 13; Other Information: PBD: Apr 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
YTTRIUM BORIDES
ELECTRIC CONDUCTIVITY
LUTETIUM CARBIDES
YTTRIUM CARBIDES
GINZBURG-LANDAU THEORY
LUTETIUM BORIDES
NICKEL CARBIDES
NICKEL BORIDES
HIGH-TC SUPERCONDUCTORS
ELECTRON-PHONON COUPLING
INTERMETALLIC COMPOUNDS
CRYSTAL STRUCTURE
TRANSITION TEMPERATURE
CRITICAL CURRENT
CURRENT DENSITY