We demonstrate that certain domain structures can be created both in ferromagnetic and antiferromagnetic spinor condensates if the initial phase is spatially modulated. Meanwhile, spin dynamics of the condensate with modulated phases exhibits exotic features in comparison with those of a condensate with a uniform phase. We expect that these phenomena could be observed experimentally using a phase-imprinting method.

Thermodynamics of a spin-1 Bose gas with ferromagnetic interactions is investigated via the mean-field theory. It is apparently shown in the specific-heat curve that the system undergoes two phase transitions, the ferromagnetic transition and Bose-Einstein condensation, with the Curie point above the condensation temperature. Above the Curie point, the susceptibility fits the Curie-Weiss law perfectly. At a fixed temperature, the reciprocal susceptibility is also in a good linear relationship with the ferromagnetic interaction.