  The high field phase diagram and magnetic properties of CeCoIn_5 below
H_c2(0) are examined from the picture regarding the high field and low
temperature (HFLT) phase as a possible Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)
vortex lattice. Crucial roles of antiferromagnetic (AFM) fluctuations enhanced
close to H_c2(0) are stressed. The FFLO vortex lattice with a longitudinal
modulation parallel to the field is stabilized compared with those with lateral
modulations as a consequence of the presence of AFM fluctuations. Further, an
unusual field-induced enhancement of the flux distribution is argued to be a
consequence of interplay between the paramagnetic depairing and AFM
fluctuation, both of which are enhanced with increasing field.
