Complex Electric Modulus Spectroscopy of (MnFe2O4)x/CuTl-1223 Nanoparticles-Superconductor Composites

Manganese ferrite (MnFe2O4) nanoparticles and Cu0.5Tl0.5Ba2Ca2Cu3O10-delta (CuTl-1223) superconducting phase were synthesized by sol-gel and solid-state reaction methods, respectively. Different contents of MnFe2O4 nanoparticles were added in CuTl-1223 superconducting matrix to get (MnFe2O4) (x) /CuTl-1223; x = 0 similar to 2.0 wt% nanoparticles-superconductor composites. Complex electric modulus spectroscopy measurements of (MnFe2O4) (x) /CuTl-1223 composites were carried out at different test frequencies from 20 Hz to 10 MHz and at different operating temperatures from 78 to 253 K to analyze and interpret the dynamical aspects of electrical transport phenomena (i.e., such as carrier hopping rate, conductivity, and blocking factor). The complex electric modulus spectra showed the effects of both grains and grain-boundaries on electrical properties. The capacitance of grain-boundaries was found higher than that of grains. The capacitive behavior of grains was increased and that of grain-boundaries was decreased with increasing operating temperature for all these samples. Blocking factor of these composites was increased with increasing contents of MnFe2O4 nanoparticles. Shifting of peaks in imaginary part of modulus spectra towards lower frequency with increasing contents of these nanoparticles showed non-Debye type relaxation phenomenon in the material.