We study the spin-s quantum Heisenberg antiferromagnetic models in a magnon
theory free of any unphysical magnon state. Because the unphysical magnon
states are completely removed in the magnon Hamiltonians and during the app
roximation process, we derive spin-s reliable Neel temperature T-N and reas
onable sublattice magnetization unified for 0 less than or equal to T less
than or equal to T-N. (C) 1999 Published by Elsevier Science B.V. All right
s reserved.