Resistive transition and flux flow mechanism in CoFe 2 O 4 nanoparticles added Cu 0.5 Tl 0.5 Ba 2 Ca 2 Cu 3 O 10−δ superconductor

(CoFe2O4)x/Cu0.5Tl0.5Ba2Ca2Cu3O10−δ {(CoFe2O4)x/CuTl-1223}; (0 ≤ x ≤ 2) nanoparticles-superconductor composites were synthesized by solid–state reaction technique and dissipative mechanism was investigated by infield measurements and analysis. Activation energy {Uo(H)} was calculated from Arrhenius plots of infield resistivity measurements. The infield resistive properties of superconductors depend upon the fluxoid motion, which causes resistive transition broadening by shifting Tc (0) towards lower temperature values. The enhancement of transition broadening is attributed to spread of upper critical field in vortex state and dissipation process with applied magnetic field. Addition of magnetic CoFe2O4 nanoparticles reduces the fluxoid motion by introducing nano-sized defects in the host CuTl-1223 superconducting matrix, which act as effective flux pinning centers. An overall increase in the activation energy Uo(H) has been observed with increasing contents of magnetic CoFe2O4 nanoparticles, which elucidate the enhanced flux pinning with increasing CoFe2O4 magnetic nanoparticles content up to x = 1.5 wt. % in CuTl-1223 superconducting matrix.