A compensated heat-pulse calorimeter for low temperatures

We describe a technique for measuring heat capacities (C(min)approximate to1 muJ/K at 0.1 K) of small solid samples at low temperatures (0.03 K<6 K) and in high magnetic fields (B<12 T). In this compensated heat-pulse technique the thermal losses are compensated through a background heating. A detailed analysis of the heat flow takes the heat input and losses into account. Test measurements on tin and YbRh2(Si0.95Ge0.05)(2) showed that the heat capacity can be determined with high precision in a fast and accurate way. This technique provides a versatile calorimeter for a wide range of heat capacities which achieves its main performance if several sample platforms are mounted and one sample is measured while the other may cool down. (C) 2004 American Institute of Physics.