Photopyroelectric study of specific heat, thermal conductivity, and thermal diffusivity of Cr2O3 at the Néel transition

A photopyroelectric technique has been used to simultaneously measure the critical behavior of specific heat, thermal conductivity, and thermal diffusivity of Cr2O3 at the antiferromagnetic-paramagnetic phase transition. An Ising-like behavior has been found for max≤3×10-3 with α=0.10±0.02 and A/A'=0.48±0.03. A possible crossover between Ising and Heisenberg behaviors has been found if is increased. Thermal diffusivity data have been fitted according to the model for a uniaxial antiferromagnet with energy conservation for ≤3×10-3 with a critical exponent b=-0.11±0.02. A correction term similar to the static correction to scaling factor has been introduced in the fitting function. No anomaly has been found in thermal conductivity. © 1994 The American Physical Society.