Superconducting and magnetotransport properties of ZnNNi3 microfibers and films

作者：Karki A B^*; Xiong Y M; Young D P; Adams P W

来源：Physical Review B, 2009, 79(21): 212508.

DOI：10.1103/PhysRevB.79.212508

• carrier density
• critical current density (superconductivity)
• fibres
• Ginzburg-Landau theory
• Hall effect
• nitrogen compounds
• powders
• sapphire
• superconducting critical field
• superconducting materials
• superconducting thin films
• superconducting transition temperature
• zinc compounds

We present the superconducting and critical current properties of ZnNNi3 in the form of annularly coated carbon microfibers and thin films. The fibers were prepared by heating 6-8 mu m diameter commercially available Ni-coated carbon fibers with Zn powder in a flowing stream of NH3 gas at 650 degrees C. The fibers had a T-c=3.75 K, which was slightly higher than that of the polycrystalline powder and an upper critical field, H-c2(0)=0.92 T. Near the transition temperature T-c, the critical current density J(c) was well described by the Ginzburg-Landau power-law form [1-(T/T-c)(2)](3/2). The extrapolation produces J(c)(0)congruent to 1.45x10(6) A/cm(2). An axial magnetic field produces an exponential decrease in the critical current density. Planar ZnNNi3 films were formed on sapphire substrates by exposing thin Ni films to a similar heat treatment as the fibers. Hall measurements on the films in the normal state revealed a carrier density, n=-1.46x10(23) cm(-3).

• 出版日期2009-6