Magnetization process in epitaxial Fe 85 Co 15 thin films via anisotropic magnetoresistance

Abstract The effects of crystalline symmetry on the magnetotransport properties of ferromagnetic alloys have been reexamined in recent years, particularly due to the role of anisotropic magnetoresistance (AMR) in the electrical detection of magnetization dynamics. This is relevant for estimating spin transport parameters such as the spin Hall angle and the damping constant. In this work, we investigated the crystal-dependent AMR in epitaxial Fe 85 Co 15 films and studied the magnetization process through the analysis of the magnetotransport properties by varying the relative orientations between the electric current, the external magnetic field, and the Fe 85 Co 15 crystallographic directions. We found that the AMR ratio depends on the current direction with respect to the crystal axes of Fe 85 Co 15 , and we determined values of 0.20% and 0.17% when the current is applied along the [110] hard and [100] easy axes, respectively. We fitted our experimental data using the Stoner–Wohlfarth model to describe the path followed by the magnetization during the magnetization process and to extract the anisotropy constants. The fitted cubic and uniaxial anisotropy constants are K c = 21 kJ m −3 and K u = 11 kJ m −3 , which are comparable with reported values from the angular variation of ferromagnetic resonance experiments. Our results contribute to the understanding of the interplay between the crystalline structure and the magnetotransport properties of Fe-rich FeCo alloys.