X-ray magnetic dichroism of antiferromagnetFe2O3: The orientation of magnetic moments observed by Fe 2px-ray absorption spectroscopy

Abstract

We report strong magnetic linear dichroism at the Fe ${\mathit{L}}_{2,3}$ edge of the antiferromagnet ${\mathrm{Fe}}_2$ ${\mathrm{O}}_3$ (hematite). The relative difference in absorption for light polarized parallel and perpendicular to the magnetic moment is as high as 40% at the Fe ${\mathit{L}}_2$ edge. The spectra are in excellent agreement with calculations of magnetic dichroism for ${\mathrm{Fe}}^{3+}$ (3${\mathit{d}}^5$). The magnetic origin of this dichroism is demonstrated by the Morin transition at ≊-10 °C, where the moments in ${\mathrm{Fe}}_2$ ${\mathrm{O}}_3$ rotate by 90°. Magnetic linear dichroism may be applied to measure the spin orientation in thin films and multilayers, and to image magnetic domains.