Specific heat, thermal diffusivity, and thermal conductivity of FeF2 at the Néel temperature.

Abstract

Photopyroelectric simultaneous measurements of the specific heat, thermal diffusivity, and thermal conductivity of single-crystalline ${\mathrm{FeF}}_{2}$ at the antiferromagnetic-paramagnetic phase transition have been performed. An Ising-like behavior has been found for the specific heat for \ensuremath{\Vert}t\ensuremath{\Vert}\ensuremath{\le}1.2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}2}$, while, in the same reduced-temperature range, the thermal-diffusivity critical behavior has been described according to a dynamic model for a uniaxial system with energy conservation with a critical exponent b=-0.11\ifmmode\pm\else\textpm\fi{}0.02. No clear power-law anomaly has been found in the thermal conductivity.