Critical Resistivity of Antiferromagnetic Semiconductors

The resistivity of nearly stoichiometric iron oxide was measured in the temperature range $78<~T<~300°$K. The temperature derivative of the resistivity, $\frac{d\rho }{\mathrm{dT}}$, in the vicinity of the critical temperature, $T_c$, was found to be proportional to ${\epsilon }^{-0.4\mathrm{}}$, where $\epsilon =\left|\frac{(T-T_c)}{T_c}\right|$. The results are explained by incorporating a normalized Ornstein-Zernike correlation function into the de Gennes-Friedel formula for critical scattering.