Critical Magnetic Behavior of Nickel near the Curie Point

Static magnetization of polycrystalline nickel spheres (diameter about 0.3 cm) has been studied in detail as a function of the magnetic field above and below the Curie point, Tc, using a vibrating sample magnetometer. Above Tc the initial magnetic susceptibility is proportional to ϵ−γ, where ϵ = ∣1 − (T/Tc)∣ and γ = 1.33 ± 0.01, T being the absolute temperature. The spontaneous magnetization, determined by the kink method, is proportional to ϵβ, where β = 0.50 ± 0.02 for ϵ < 5 × 10−3 and β = 0.34 ± 0.02 for ϵ > 5 × 10−3. The magnetization at Tc is proportional to H , where Hi is the internal magnetic field and δ = 4.17 ± 0.05. These results are compared with the power values obtained by other investigators and are discussed from the viewpoint of various theoretical models.