  Neutrino properties can play a crucial role in determining the
matter-antimatter asymmetry of the universe if thermal leptogenesis is the
correct solution to the baryogenesis problem. Owing to this, the study of
neutrino models goes beyond the mere purpose of generating tiny neutrino
masses, and it is natural to incorporate the puzzle of the cosmic baryon
asymmetry. To this end, we have investigated several different extensions of
the neutrino model based on the type I seesaw mechanism with particular
emphasis on their leptogenesis implications.
