Low Temperature Specific Heat of RMn2Compounds with the Hexagonal C14 Structure (R=Y, Yb and Th)

The specific heat of C14 YMn 2 , YbMn 2 and ThMn 2 was measured in the temperature range of 1.4 K to 10 K. The huge values of specific heat were observed for all compounds. The origin of the huge values of specific heat are considered to be derived from two mechanisms. For C14 YMn 2 and ThMn 2 , those are ascribed to the excitations of large spin fluctuations of Mn moments. On the other hand, the extraordinary large value of YbMn 2 is due to the paramagnetic Yb moment.