Measurement of magnetization using domain compressibility in CoFeB films with perpendicular anisotropy

N. Vernier, J. P. Adam, S. Eimer, G. Agnus, T. Devolder, T. Hauet, B. Ockert, D. Ravelosona

Published 2013-07-24Version 1

We present a method to map the saturation magnetization of soft ultrathin films with perpendicular anisotropy, and we illustrate it to assess the compositional dependence of the magnetization of CoFeB(1 nm)/MgO films. The method relies on the measurement of the dipolar repulsion of parallel domain walls that define a linear domain. The film magnetization is linked to the field compressibility of the domain. The method also yields the minimal distance between two walls before their merging, which sets a practical limit to the storage density in spintronic devices using domain walls as storage entities.