Orbital magnetic moments in SrRuO3 epitaxial thin films with interfacially controlled magnetic anisotropy

Abstract

Using x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) spectroscopy, we evaluated the orbital magnetic moments of itinerant ferromagnet $\mathrm{SrRu}{\mathrm{O}}_{3}$ (SRO) epitaxial thin films with interfacially controlled magnetic anisotropy. We found that the orbital moment is closely correlated with the SRO's magnetic anisotropy, which can be controlled by interfacially engineering the $\mathrm{Ru}{\mathrm{O}}_{6}$ octahedral rotations. For the monoclinic film with magnetization along the direction 45\ifmmode^\circ\else\textdegree\fi{} from the out-of-plane direction, the orbital moment is $\ensuremath{\approx}\ensuremath{-}0.1\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}/\mathrm{Ru}$ along the magnetic easy axis direction and is aligned antiparallel to the direction of the spin magnetic moments. For the tetragonal film with in-plane magnetization, on the other hand, the out-of-plane component of the orbital moment is as small as $\ensuremath{\approx}\ensuremath{-}0.04\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}/\mathrm{Ru}$, accounting for the film's in-plane magnetic anisotropy. Our results highlight that the magnetic anisotropy of SRO can be controlled by engineering the orbital magnetic moment through the octahedral distortions.