One-Dimensional Metastable and Saddle Magnetization Profiles of Confined Ferromagnetic Systems with Effective Quadratic Anisotropy Under Arbitrary External Fields.

We present a mathematical procedure to obtain analytical profiles of energy extremals applicable to a wide variety of effectively one-dimensional ferromagnetic systems. If the energy functional can be approximated by an effective local quadratic anisotropy and Heisenberg exchange, the magnetization profiles can be obtained in terms of Jacobi Elliptic Functions under the assumption that the magnetization follows a circular path on the unit sphere. Using these functions, it is possible to estimate energy barriers for thermal activation as the size of the device is increased. In previous works, fields were applied either parallel [1] or perpendicular [2] to the easy anisotropy axis. Our recently developed procedure works at any arbitrary direction of the magnetic field. Our results can be used even in the presence of Dzialoshinskii-Moriya interactions and are important for applications of magnetic information storage.

[1] Kirsten Martens et al. PRB 73, 054413 (2006)

[2] Capriata et al. arXiv:2305.09558