OXYGEN ORDERING IN YBA2CU3OZ - A MONTE-CARLO STUDY

A two dimensional lattice ps model describing the ordering in the Cu-O basal plane of YBa2Cu3Oz is studied using Monte Carlo techniques. The phase diagram is found to consist of tetragonal and orthorhombic phas es. Quantities of experimental interest, such as the paramagnetic Curi e constant, the amount of monovalent copper, and the concentration of oxygen holes transferred from the O-Cu-O chains, are calculated. Resul ts are compared to experimental findings as well as results of prior t heoretical investigations on the model.