  We propose to localize spin mixing dynamics in a spin-1 Bose-Einstein
condensate by a temporal modulation of spin exchange interaction, which is
tunable with optical Feshbach resonance. Adopting techniques from coherent
control, we demonstrate the localization/freezing of spin mixing dynamics, and
the suppression of the intrinsic dynamic instability and spontaneous spin
domain formation in a ferromagnetically interacting condensate of $^{87}$Rb
atoms. This work points to a promising scheme for investigating the weak
magnetic spin dipole interaction, which is usually masked by the more dominant
spin exchange interaction.
