ИСТИНА

The spin-orbit Dzyaloshinskii–Moriya (DM) interaction EDM=D•[s1×s2] can induce weak ferromagnetism by small canting of neighboring magnetic moments s1 and s2 in antiferromagnets. The local direction of the DM vector D has been experimentally determined for the first time in the canted antiferromagnetic FeBO3 crystal. The technique of interference between magnetic and resonant channels in synchrotron x-ray scattering was exploited. The phase of antiferromagnetic ordering (and scattering) was fixed by external magnetic field and the phase of resonant scattering was calculated with FDMNES program. Similar experiments have been also performed for MnCO3 and CoCO3 crystals. For Fe2O3 hematite crystal, the technique of interference between magnetic and multiple diffraction channels has been used. The experimental measurements are supported by ab initio calculations of the DM interaction. The first-principles calculations have been performed with Local Density Approximation incorporating the on-site Coulomb interaction U and the Spin-Orbit coupling (LDA+U+SO). It was found how DM interaction depends on displacements of oxygen atoms. These experimental and theoretical approaches open up new possibilities for exploring, modeling and exploiting novel magnetic and multiferroic materials.