Heisenberg antiferromagnet on the square lattice for S >= 1

Theoretical predictions of a semiclassical method-the pure-quantum self-con sistent harmonic approximation-for the correlation length and staggered sus ceptibility of the two-dimensional quantum Heisenberg antiferromagnet (2DQH AF) on the square lattice agree very well with recent quantum Monte Carlo d ata for S=1, as well as with experimental data for the S=5/2 compounds Rb2M nF4 and KFeF4. The theory is parameter free and can be used to estimate the exchange coupling: for KFeF4 we find J= 2.33+/-0.33 meV, consistent with p reviously determined values. On this basis, the adequacy of the quantum non linear a model approach in describing the 2DQHAF when S greater than or equ al to 1 is discussed. [S0163-1829(98)02742-8].