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, results yield critical parameters β = 0.370 +- 0.006, B = 1.10 +- 0.04, γ = 1.30 +- 0.02, and GAMMA=0.397 +- 0.012. The value of γ 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 a1 = 2.56, k1 = 1.025 and a2 = 1.78, k2 = 0.718. The data predict specific-heat parameters α = -0.04 +- 0.03 and A/A ' = 1.31 +- 0.05, in agreement with experimental results analyzed with nonsingular correction terms