Faraday rotation near the Curie point of EuO

The static magnetic properties of EuO near the Curie point have been measured using Faraday rotation. Comparison between magnetometer data reveals a small nonlinear term in the relation between rotation and magnetization. With this correction, our results yield critical parameters $\beta =0.370\mathrm{}\pm 0.006$, $B=1.10\mathrm{}\pm 0.04$, $\gamma =1.30\mathrm{}\pm 0.02$, and $\Gamma =0.397\mathrm{}\pm 0.012$. The value of $\gamma$ agrees with other static experiments, but disagrees with neutron-scattering measurements and with theory. All the data can be scaled using these exponents, and are consistent with the two proposed parametric equations of state, with coefficients $a_1=2.56\mathrm{}$, $k_1=1.025\mathrm{}$ and $a_2=1.78\mathrm{}$, $k_2=0.718\mathrm{}$. Our data predict specific-heat parameters $\alpha =-0.04\mathrm{}\pm 0.03$ and $\frac{A}{A^{\prime }}=1.31\mathrm{}\pm 0.05$, in agreement with experimental results analyzed with nonsingular correction terms.