PHOTOPYROELECTRIC STUDY OF SPECIFIC-HEAT, THERMAL-CONDUCTIVITY, AND THERMAL-DIFFUSIVITY OF CR2O3 AT THE NEEL 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 \t(max)\ less-than-or-equal-to 3 X 10(-3) with alpha = 0.10 +/- 0.02 and A/A' = 0.48 +/- 0.03. A possible crossover between Ising and Heisenberg behaviors has been found if \t(max)\ is increased. Thermal diffusivity data have been fitted according to the model for uniaxial antiferromagnet with energy conservation for \t(max)\ less-than-or-equal-to 3 X 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.