Specific heat of Pr_1-xNd_xOs₄Sb₁₂

Filled skutterudites are the compounds that show the formula RM₄X₁₂. R is the rare earth metal, M is the transition metal, and X is the pnictogen. They will show rich varieties of strongly correlated electron behaviors, which attract our interest. The sample we focus on is a doping system, Pr_1-xNd_xOs₄Sb₁₂. PrOs₄Sb₁₂ show unconventional superconductivity, while NdOs₄Sb₁₂ exhibit ferromagnetism at low temperature. Therefore, there is a competition between two properties. In order to understand the compound better, we do the heat capacity measurement from 11K to 300K. From the curve of the specific heat of Pr_1-xNd_xOs₄Sb₁₂, parameters can be extracted out by the curve fitting with a combination of the Debye, Einstein, and Sommerfeld models. These parameters include Debye temperature, Einstein temperature, and electronic specific heat coefficient and can show the properties of the materials, such as the stiffness of the crystal structure, the rattling effect of the rare earth metal, and electron correlation. From the data analysis, we try to find out the trend of parameters depending on Nd concentration.