Using x-ray magnetic linear dichroism (XMLD) for magnetometry requires detailed knowledge of its dependence on the relative orientation of polarization, magnetic moments, and crystallographic axes. We show that ${\mathrm{Ni}}^{2+}$ $L_{2,3}$ XMLD in cubic lattices has to be described as a linear combination of two fundamental spectra—not one as previously assumed. The spectra are calculated using atomic multiplet theory and the angular dependence is derived from crystal field symmetry. Applying our results to $\mathrm{Co}/\mathrm{NiO}(001)$ interfaces, we find perpendicular coupling between Ni and Co moments.

• Received 30 August 2006

DOI:https://doi.org/10.1103/PhysRevLett.98.197201