The nucleation and growth kinetics of magnetic domains below Curie temperature during thermomagnetic recording in a typical compensation point writing material, GdTbFeCo, were investigated with a dynamic tester using both pulsed and cw laser beams. Nucleation of domain is shown to be more difficult than growth. Furthermore, both nucleation and growth of domains are rather nonuniform. The implications of these observations are discussed. © 1989 The Japan Society of Applied Physics.