THEORY OF SHORT-RANGE MAGNETIC ORDER FOR THE T-J MODEL

We present a self-consistent theory of magnetic short-range order base d on a spin-rotation-invariant slave-boson representation of the 2D t- J model. In the functional-integral scheme, at the nearest-neighbour p air-approximation level, the bosonized t-J Lagrangian is transformed t o a classical. Heisenberg model with an effective (doping-dependent) e xchange interaction which takes into account the interrelation of ''it inerant'' and ''localized'' magnetic behaviour. Evaluating the theory in the saddle-point approximation, we find a suppression of antiferrom agnetic and incommensurate spiral long-range-ordered phases in the fav our of a paramagnetic phase with pronounced antiferromagnetic short-ra nge correlations.