Low-temperature scaling of the susceptibility of Ni films

Measurement of low field ac susceptibility of Ni thin films over the temperature range of 5--3000.3em0exK reveals a surprising power law scaling. The temperature-dependent part of the normalized susceptibility, χ_∥∕MS-χᵣₒₜ∕MS, where χ_∥ is the initial susceptibility for in-plane magnetization, χᵣₒₜ is the domain rotation contribution, and MS is the saturation magnetization, scales with the nonlinear reduced temperature as t^-2 over the entire temperature range, where t=(T-TC)∕(T+TC) and TC is the Curie temperature. Thickness and reduced temperature dependences are completely decoupled. This result implies that domain wall motion does not contribute to the low field susceptibility.