The critical thermal expansion of gadolinium

Measurements have been made of the critical thermal expansion of single crystals of gadolinium, prepared by solid state electrotransport processing. Although the expansion data can be fitted to a simple power law with exponents λ⁺=?0.25, γ^?=?0.33, these values are not predicted by theory and a discontinuity remains at T_c=293.620K. It is suggested that the results relate to a region of crossover to uniaxial dipolar behaviour.