Magnetic studies of phase separation in La2CuO4+δ single crystals

The phase separation effect in La2CuO4.015 single crystal has been studied by magnetic susceptibility and EPR experiments. The experiments confirm the percolative phase separation model based on the concept of magnetic polarons formed by hole doping. It has been shown that the superconducting subphase has specific spatial structure which is responsible for unconventional low temperature behavior of susceptibility. The EPR signal as well as the paramagnetic contribution to the low-temperature susceptibility have been shown to arise from isolated Cu2+ ions located inside the phase domain walls. (orig.)