Dipole-dipole interactions and the critical resistivity of gadolinium.

Abstract

Results are presented for the electrical resistivity of a c-axis single crystal of high-purity gadolinium metal in the immediate vicinity of the Curie temperature. Numerical analysis reveals that the data are not well described by the usual power laws in (T-${T}_{c}$)/${T}_{c}$ but tend to exhibit a change in effective slope at ${T}_{c}$ which can be described by classical Landau theory with logarithmic corrections. This is interpreted in terms of the dipole-dipole interactions, which are shown to become important at about 1 K above ${T}_{c}$. We suggest that gadolinium is a uniaxial dipolar ferromagnet in the asymptotic critical-behavior regime.