The ac magnetic susceptibility of a ${\mathrm{NdGaO}}_3$ single crystal has been measured along the three principal crystallographic axes in the temperature range from 50 K down to 0.07 K. The data obtained indicate that the compound orders antiferromagnetically at $T_N\approx 1\mathrm{K}$ with the sublattice moments parallel to [001], which is consistent with earlier neutron-diffraction results. The data are interpreted in terms of the Ising model on the simple tetragonal lattice in the quasi-two-dimensional regime: the intralayer exchange is relatively strong and antiferromagnetic, $J_{\perp }/k=-0.70\mathrm{K},$ whereas the interlayer exchange is ferromagnetic and an order of magnitude weaker, $J_{\parallel }/k=0.07\mathrm{}\mathrm{K}.$ This model also describes well the earlier specific-heat data. The $g$ factors deduced from the low-temperature susceptibility, $g_x=1.84,$ $g_y=2.41,$ $g_z=2.73,$ are in reasonable agreement with electron paramagnetic resonance measurements on Nd-doped ${\mathrm{LaGaO}}_3.$

• Received 3 February 1998

DOI:https://doi.org/10.1103/PhysRevB.58.798