Enhanced anomalous Hall effect in Fe nanocluster assembled thin films

Abstract

An enhanced anomalous Hall effect is observed in heterogeneous uniform Fe cluster assembled films with different film thicknesses (t_a = 160–1200 nm) fabricated by a plasma-gas-condensation method. The anomalous Hall coefficient (R_s) at t_a = 1200 nm reaches its maximum of 2.4 × 10⁻⁸ Ω cm G⁻¹ at 300 K, which is almost four orders of magnitude larger than bulk Fe. The saturated Hall resistivity (ρ^A_xy) first increases and then decreases with the increase of temperature accompanied by a sign change from positive to negative. Analysis of the results revealed that ρ^A_xy decreases with increasing longitudinal resistivity (ρ_xx) on a double-logarithmic scale and obeys a new scaling relation of log(ρ^A_xy/ρ_xx) = a₀ + b₀ log ρ_xx.