  Low-spin states in the neutron-rich, N = 90 nuclide $^{146}$Ba were populated
following $\beta$-decay of $^{146}$Cs, with the goal of clarifying the
development of deformation in Ba isotopes through delineation of their
non-yrast structures. Fission fragments of $^{146}$Cs were extracted from a
1.7-Ci $^{252}$Cf source and mass-selected using the CARIBU facility.
Low-energy ions were deposited at the center of a box of thin $\beta$
detectors, surrounded by a high-efficiency HPGe array. The new $^{146}$Ba decay
scheme now contains 31 excited levels extending up to ~2.5 MeV excitation
energy, double what was previously known. These data are compared to
predictions from the Interacting Boson Approximation (IBA) model. It appears
that the abrupt shape change found at N = 90 in Sm and Gd is much more gradual
in Ba and Ce, due to an enhanced role of the $\gamma$ degree of freedom.
