  We investigate the physical properties of the Shastry-Sutherland lattice
material BaNd$_2$ZnO$_5$. Neutron diffraction, magnetic susceptibility, and
specific heat measurements reveal antiferromagnetic order below 1.65 K. The
magnetic order is found to be a 2-$\boldsymbol{Q}$ magnetic structure with the
magnetic moments lying in the Shastry-Sutherland lattice planes comprising the
tetragonal crystal structure of BaNd$_2$ZnO$_5$. The ordered moment for this
structure is 1.9(1) $\mu_B$ per Nd ion. Inelastic neutron scattering
measurements reveal that the crystal field ground state doublet is well
separated from the first excited state at 8 meV. The crystal field Hamiltonian
is determined through simultaneous refinement of models with both the LS
coupling and intermediate coupling approximations to the inelastic neutron
scattering and magnetic susceptibility data. The ground state doublet indicates
that the magnetic moments lie primarily in the basal plane with magnitude
consistent with the size of the determined ordered moment.
