  At zero temperature the sublattice magnetization of the quantum spin-1/2
Heisenberg antiferromagnet on a body-centered cubic lattice with competing
first and second neighbor exchange (J1 and J2) is investigated using the
non-linear spin wave theory. The zero temperature phases of the model consist
of a two sublattice N\'{e}el phase for small J_2 (AF_1) and a collinear phase
at large J_2 (AF_2). We show that quartic corrections due to spin-wave
interactions enhance the sublattice magnetization in both the AF_1 and the AF_2
phase. The magnetization corrections are prominent near the classical
transition point of the model and in the J_2> J_1 regime. The ground state
energy with quartic interactions is also calculated. It is found that up to
quartic corrections the first order phase transition (previously observed in
this model) between the AF_1 and the AF_2 phase survives.
