Physical observables of a macrosystem are functions of state variables that uniquely define the macroscopic state. However, the explicit impact of these variables on the behaviors of magnetoresistance (MR) has not been fully explored. Here, angular-dependent MR of textured cobalt (002) films, which possess a uniaxial magnetocrystalline anisotropy (MCA) with the easy axis ($z$ axis) perpendicular to the isotropic film plane ($xy$ plane), is investigated experimentally and theoretically with two vector state variables: magnetization $\mathbf{m}$ and easy axis $\mathbf{n}$ of the MCA. When the current is applied along the $x$ direction, we found that the angular-dependent MR in different measurement planes shows these distinct scattering mechanisms: it is governed solely by scattering related to m—the conventional anisotropic MR (AMR)—in the $xy$ plane, by the electron scattering related to n in the $yz$ plane (crystalline AMR), and by a combination of both in the $xz$ plane. Notably, the crystalline AMR in the $yz$ plane exhibits a form similar to that of the uniaxial MCA energy. Both the twofold and fourfold terms are independent of the film thickness, and the amplitude of the twofold term is proportional to the twofold constant of MCA. Our results provide a framework for understanding and engineering MR by harnessing the MCA constant.

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• Magnetoresistance
• Magnetotransport
• Spin caloritronics
• Ferromagnets