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It is shown how soft X-ray nanospectroscopy maps of powders (particle size ∼200 nm) can be analyzed to quantitatively retrieve X-ray linear dichroism (XLD) parameters. A computational modeling procedure is described that can be used in conjunction with Monte Carlo simulations to prove statistical dissimilarity of XLD parameters between different samples., X-ray linear dichroism (XLD) is a fundamental property of many ordered materials that can for instance provide information on the origin of magnetic properties and the existence of differently ordered domains. Conventionally, measurements of XLD are performed on single crystals, crystalline thin films, or highly ordered nanostructure arrays. Here, it is demonstrated how quantitative measurements of XLD can be performed on powders, relying on the random orientation of many particles instead of the controlled orientation of a single ordered structure. The technique is based on a scanning X-ray transmission microscope operated in the soft X-ray regime. The use of a Fresnel zone plate allows X-ray absorption features to be probed at ∼40 nm lateral resolution – a scale small enough to probe the individual crystallites in most powders. Quantitative XLD parameters were then retrieved by determining the intensity distributions of certain diagnostic dichroic absorption features, estimating the angle between their transition dipole moments, and fitting the distributions with four-parameter dichroic models. Analysis of several differently produced ZnO powders shows that the experimentally obtained distributions indeed follow the theoretical model for XLD. Making use of Monte Carlo simulations to estimate uncertainties in the calculated dichroic model parameters, it was established that longer X-ray exposure times lead to a decrease in the amplitude of the XLD effect of ZnO.

A high-spin state of SrRuO3 at the interface and large magnetic coupling were observed in SrRuO3/LaNiO3 superlattices. X-ray absorption spectroscopy and X-ray linear dichroism results show preferential occupation of the d3z2-r2 orbitals. The origin of the high-spin state in SrRuO3 and the large-scale magnetic coupling is closely related to the orbital reconstruction. The reduced energy of the d3z2−r2 orbitals and enhanced densities of the eg of SrRuO3 contribute to the interface magnetic moment. The orbital occupancy is strongly correlated with the interface magnetic properties, thereby extending the concept of orbital degrees of freedom modulation on magnetic coupling properties. Impact statement A high-spin state in SRO at the interface and large magnetic coupling is observed in SRO/LNO superlattices and the origin of these properties is closely related to orbital reconstruction.