  Based on the construction of generalized Halperin wave functions, we predict
the possible existence of a large class of broken spin symmetry states in
bilayer quantum Hall structures, generalizing the recently suggested canted
antiferromgnetic phase to many fractional fillings. We develop the appropriate
Chern-Simons theory, and establish explicitly that the low-lying neutral
excitation is a Goldstone mode and that the charged excitations are bimerons
with continuously tunable (through the canted antiferromagnetic order
parameter) electric charge on the individual merons.
