抄録
Phase transition of frustrated systems is very important topic and interesting phenomenon. In frustrated systems, the specific heat shows characteristic behavior due to many degenerate ground states. We review the feature of the phase transition and that of frustrated systems in a viewpoint of the entropy. We also review interesting phenomena of the stacked triangular antiferromagnets and that of the kagome antiferromagnets with easy axis anisotropy. Finally, we show recent studies of frustrated spin systems.