Scaling behavior of magnetization in the critical region of a-Fe_90-xCo_xZr₁₀ alloys

Abstract

Contrary to earlier reports, a detailed ferromagnetic resonance (FMR) study in the critical region of Fe_90-xCo_xZr₁₀ alloys with 0≤ x≤10 shows that the critical exponents β and γ for spontaneous magnetization and initial susceptibility, respectively, which characterize the ferromagnetic (FM)-paramagnetic (PM) phase transition at the Curie temperature, T_C, possess values which are close to the three-dimensional Heisenberg values and are independent of composition. The fraction of spins that participates in the FM-PM phase transition possesses a value of 11% for the alloy with x=0 and increases with Co concentration x. The peak-to-peak FMR linewidth is governed by the Landau-Lifshitz-Gilbert relaxation mechanism in the critical region and the Lande splitting factor g and the Gilbert damping parameter λ are independent of temperature. While λ decreases with x, g has a constant value of 2.07±0.02.