  A self-consistent spin-fluctuation theory is developed to obtain T_N vs. U
for the half-filled Hubbard antiferromagnet in the whole U/t range. Good
agreement is obtained in the strong coupling limit with the high-temperature
series-expansion result for the equivalent Heisenberg model. Quantum,
spin-fluctuation correction to the sublattice magnetization is also obtained
for all U at the one-loop level. A spin picture is used throughout, and quantum
effects are incorporated through transverse spin fluctuations, which are
evaluated in the RPA using a new method.
