Abstract by Grace Neilsen
Chemistry and Biochemistry
Detecting Oxygen Vacancies in Singly and Co-Doped Cerium Oxides
Heat capacity measurements provide insights into the lattice of a material and any defects in the lattice. Our lab has recently proposed a model specifically for quantifying lattice vacancies based on the linear term of the heat capacity. However, it was unclear whether or not this model could detect both random and clustered vacancies. To investigate this, we measured the heat capacity of singly (Nd or Sm) doped and co-doped (Nd and Sm) cerium oxides. These samples were used because they have a known vacancy concentration, and these expected values were then compared to the vacancy concentrations derived from the linear-term model. This comparison showed that this model could accurately predict near randomly distributed vacancies. However, predictions were low by approximately an order of magnitude when vacancies become clustered. This work verifies the dependability of the linear-term model thereby providing a way to quantify the amount of vacancy clustering in a material.