Electron hole ordering in La2CuO4-δ

Phase separation in La cuprate superconductors is studied by NMR, NQR and microwave (mw) absorption measurements. The comparison of all these data leads to a unique phase separation temperature (T = 230 K) at which the separation into a hole rich (metallic and superconducting) and a hole poor (insulating and antiferromagnetic) phase occurs. There is indication that this phase separation is accompanied by oxygen diffusion. Numerical simulations of the Monte Carlo type and a stochastic Langevin equation approach are applied in order to model the experimental data. (orig.)