The Open Superconductors Journal

2011, 3 : 1-6
Published online 2011 February 3. DOI: 10.2174/1876537801103010001
Publisher ID: TOSUPERJ-3-1

Scaling Behavior of Current- Voltage Characteristics of YCaBaCuO Polycrystalline Samples

E. Nazarova , K. Nenkov , K. Buchkov and A. Zahariev
Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria.

ABSTRACT

I-V characteristics of polycrystalline Y1-xCaxBa2Cu3O7-δ samples (x=0.025 and 0.20) have been measured at different temperatures and magnetic fields in the range 0.1 T-6.9 T. The scaling behavior has been established for both samples at all magnetic fields. The dynamic exponent z displays some morphology dependence with higher value for small grain size sample Y0.8Ca0.2Ba2Cu3O7-δ. The static exponent ν has been determined from ρ vs. T dependence at given magnetic field. The critical exponents are field independent with one only exception (ν - for Y0.975Ca0.025Ba2Cu3O7-δ sample). This is connected with the special interrelation between the vortex correlation length, ξ, and intervortex spacing α (ξ ≤ α) at all magnetic fields above Tg for this sample and its better pinning.

Keywords:

YCaBaCuO polycrystalline samples, I-V characteristics, scaling behavior, critical exponents. PACS: 74.72.- h; 74.25.Uv; 74.25.Wx.