Abstract :
Composites Y3/4Lu1/4Ba2Cu3O7+Y3Fe5O12 modeling random network superconductor–ferrimagnetic–superconductor have been prepared and their transport properties (temperature dependences of resistivity ρ and critical current density jc, current–voltage characteristics) have been studied. Below the superconducting transition temperature Tc, the ρ(T) dependences exhibit a kink at some temperature Tm. The crossover of current–voltage characteristics from ohmic-like behavior in range Tm/Tc to non-linear one below Tm is observed. Transport properties of the ‘benchmark’ composites Y3/4Lu1/4Ba2Cu3O7+Y3Al5O12 are typical for network superconductor–insulator–superconductor Josephson junction. The behavior observed for Y3/4Lu1/4Ba2Cu3O7+Y3Fe5O12 composites is attributed to peculiarities of supercurrent carriers tunnelling through ferrimagnetic barriers.
