Bulk-sensitive magnetic microscope utilizing x-ray magnetic circularly polarized emission

We report a bulk-sensitive x-ray magnetic microscope that exploits a new magneto-optical effect in x-ray emission, referred to as x-ray magnetic circularly polarized emission (XMCPE). An advantage of XMCPE is a large magnetic dichroic effect for 3d transition-metal elements in the hard x-ray region, which enables the realization of a bulk-sensitive microscope suited to iron- and cobalt-rich ferromagnetic materials. We constructed a scanning microscope with 10 μm lateral resolution. A key element is a Montel-type collimating mirror that widely collects the divergent x rays emitted from a sample and converts them into a well-collimated x-ray beam, which is required for circular polarization analysis. Owing to this mirror, the obtained XMCPE spectra of metallic iron exhibited strong intensity and a large magnetic dichroic effect. The performance of the microscope is also demonstrated by the acquisition of magnetization images of an electrical steel sheet with an insulating coating.