Probing magnetic anisotropy effects in epitaxial CrO₂ thin films

The magnetic anisotropy in ferromagnetic chromium dioxide thin films (Tc∼393 K) grown epitaxially on (100) TiO2 substrates, is probed using precise rf transverse susceptibility (χT) measurements. Singular peaks in χT are observed that are associated with the anisotropy (±HK) and switching (±Hs) fields in CrO2. Theoretical calculations of χT based on a simple coherent rotation model display remarkable agreement with the experimental data, indicating that these thin films behave like single-domain magnetic particles. Magneto-elastic contributions to the total anisotropy energy are needed to describe the evolution of χT peaks at lower temperatures.