  From small-angle neutron scattering studies of the flux line lattice (FLL) in
CeCoIn5, with magnetic field applied parallel to the crystal c-axis, we obtain
the field- and temperature-dependence of the FLL form factor, which is a
measure of the spatial variation of the field in the mixed state. We extend our
earlier work [A.D. Bianchi et al. 2008 Science 319, 177] to temperatures up to
1250 mK. Over the entire temperature range, paramagnetism in the flux line
cores results in an increase of the form factor with field. Near H_c2 the form
factor decreases again, and our results indicate that this fall-off extends
outside the proposed FFLO region. Instead, we attribute the decrease to a
paramagnetic suppression of Cooper pairing. At higher temperatures, a gradual
crossover towards more conventional mixed state behavior is observed.
