Emergence of superconductivity in mixture of nonsuperconducting ceramics La2CuO4 and La1.56Sr0.44CuO4
Samples of composite material fabricated by means of annealing of mixture of nonsuperconducting ceramics La2CuO4 and La1.56Sr0.44CuO4 are studied. Areas of superconducting La1.85Sr0.15CuO4 arise at boundaries of osculating nonsuperconducting granules. The fraction of the superconducting phase in the samples increases with increasing the annealing time. The magnetotransport behavior of obtained samples at low (~ 100 Oe) magnetic fields are defined by properties of week links network that is formed in superconducting areas. At high fields the system behavior is defined by a magnetization of the disconnected superconducting islands. The average size of the superconducting area has been estimated from an extended critical state model. A model describing the magnetic and transport properties of the samples in low magnetic fields has been constructed.