Beyond element-specific magnetism: resolving inequivalent Nd crystal sites in Nd2Fe14B

We show how basic crystallography can be combined with resonant scattering of circularly polarized (CP) X-rays to extract element- and site-specific magnetism in crystals. This is achieved by combining the inherent element specificity of resonance scattering with the symmetry properties of the crystal, which results in enhanced/suppressed scattering amplitudes from certain lattice sites under particular diffraction conditions. We used this method to measure the magnetic response of inequivalent Nd sites in Nd₂Fe₁₄B single crystal (4f and 4g sites in Wyckoff notation) through the crystal´s magnetization reversal at room temperature and through the spin reorientation transition at lower temperatures. This approach might prove very valuable in studies of magnetocrystalline anisotropy in complex materials with multiple elements and crystal sites.