Mixing-typed antiferroquadrupolar ordering in YbSb

Specific heat and magnetization measurements have been performed with a low carrier heavy fermion compound YbSb. Successive phase transitions at 0.5 K and 5 K were observed by specific heat measurements under external magneti c fields up to 12 T. The transition temperature at 5 K increases with incre asing external magnetic field. The magnetization measurements indicate the existence of field induced magnetic ordered moments at 5K. These magnetic p roperties of the phase transition at 5K are discussed in terms of a mixing- typed antiferroquadrupolar ordering model with a Gamma (6) Kramers doublet as the crystalline electric field ground state.