Unusual anisotropic magnetic orbital moment obtained from x-ray magnetic circular dichroism in a multiferroic oxide system

The electric-field control of $d$-electron magnetism in multiferroic transition metal oxides is attracting widespread interest for the underlying fundamental physics and next generation spintronic devices. Here, we report an extensive study $3d$ magnetoelectric Ga$_{0.6}$Fe$_{1.4}$O$_3$ (GFO) epitaxial films by polarization dependent x-ray absorption spectroscopy. We found a non-zero integral magnetic circular dichroism, with sign depending upon relative orientation between external field crystallographic axes. %By reliably enlarging limit spin orbital sum rules, which usually holds materials where ions exhibit unique crystal symmetry This finding translates sign-reversal average Fe moments. Large Fe-displacements, among some octahedral sites, lower system producing anisotropic paths Fe-O bondings giving rise to large orbital-lattice interaction akin preferential direction moment. latter may lead partial re-orientation moment under that, combined ferrimagnetic nature GFO, can qualitatively explain observed XMCD integral. results suggest that over local oxygen octahedra offer suitable leverage manipulation effective moments systems.