Simultaneous measurement of thethermal diffusivity and specific heat near phase transitions

A technique for measuring the absolute thermal diffusivity along with the relative specific heat is introduced which is readily adaptable to a wide variety of applications. The thermal diffusivity and specific heat of CoO, near the antiferromagnetic transition; of SrTiO₃, near the structural phase transition; of Cr, near the first-order SDW-paramagnetic transition; and of EuO, near the ferromagnetic Curie point were measured. Except for SrTiO₃, the thermal diffusivities are found to mirror the specific heats, with no evidence for anomalies in the thermal conductivities, contrary to some earlier reports. A step increase in the thermal conductivity is observed on passing through the structural transition of SrTiO₃ from below which is of the same relative size as the step decrease of specific heat at T_c.