Finite pulse relaxation calorimetry and specific heat of NdOs$_4$Sb$_{12}$*

The compound NdOs$_4$Sb$_{12}$ is a mean-field ferromagnet at about 1 K. As inferred from specific heat measurements below 10 K, the electronic specific heat coefficient of this compound is very large ($\sim$ 520 mJ/mol-K$^2$). Intriguingly, a recent ultrasonic measurement shows that this compound has double ultrasonic dispersions at $\sim$15 K and 40 K. We have used our newly developed relaxation calorimeter to measure the specific heat of NdOs$_4$Sb$_{12}$ in the temperature range 11 K to 300 K. In this presentation, we will describe the experimental setup used for the finite pulse relaxation calorimetry in a crycooler and the results of our measurements on the NdOs$_4$Sb$_{12}$ sample.