  Magneto-optical imaging in YBa2Cu3O7-d with tilted columnar defects (CD's)
shows an asymmetric critical-state field profile. The observed hysteretic shift
of the profile ridge (trough) from the center of the sample is explained by
in-plane magnetization originated from vortex alignment along CD's. The
extracted ratio of the in-plane to out-of-plane magnetization component has a
maximum at 1/5 of matching field ($B_\Phi$) and disappears above $B_\Phi/3$,
suggesting a reduction of interlayer coherence well bellow $B_\Phi$ in the Bose
glass phase. Implications are discussed in comparison with the vortex liquid
recoupling observed in irradiated Bi2Sr2CaCu2O8+y.
