Critical indexes of the nickel thermal diffusivity

Using the laser flash method, the thermal diffusivity (a) of nickel was measured in the temperature range of 300–1680 K with a detailed study of the region near the Curie temperature T c = 628 K. The initial experimental data in the field of magnetic phase transformation were processed by the scaling dependence, and the critical thermal diffusivity indexes (α, α’) were obtained below and above T c : α = 0.86 and α’ = 0.26, which in absolute value significantly exceed the critical heat capacity index. The possible reasons for this difference have been briefly discussed.