Anisotropic galvanomagnetic effects in single-crystal Fe(001) films elucidated by a phenomenological theory

TL;DR

This study combines phenomenological theory and experimental measurements to fully characterize the angular dependencies of galvanomagnetic effects in single-crystal Fe(001) films, confirming theoretical predictions and clarifying symmetry-related effects.

Contribution

It provides a complete angular dependency analysis of AMR and PHE in Fe(001) films based on crystal symmetry, validated by experiments, and clarifies the symmetry constraints on these effects.

Findings

Intrinsic effects are independent of magnetic field strength.

No four-fold in-plane angular dependence in PHE due to symmetry constraints.

Phenomenological theory accurately predicts angular dependencies.

Abstract

Utilizing the phenomenological theory based on crystal symmetry operation, we have established the complete angular dependencies of the galvanomagnetic effects, encompassing both anisotropic magnetoresistance (AMR) and the planar Hall effect (PHE), for the ferromagnetic films with C4v symmetry. These dependencies were experimentally confirmed via comprehensive angular-mapping of AMR and PHE in single-crystal Fe(001) films at room temperature. We demonstrated that the intrinsic magnetization-induced effects are independent of the field strength by carefully separating the field-induced and magnetization-induced galvanomagnetic effects. Our theoretical and experimental findings highlight the absence of in-plane four-fold angular dependence in PHE, a feature prohibited by the Onsager relation in systems with C4 symmetry. This study affirms that the universal angular dependencies of AMR and PHE in single crystals can be accurately predicted by the conventional phenomenological theory.