[en] We report on our work on magnetic properties and their correlation with local structure in Fe-Sc nanoglasses. Samples were synthesized with a nominal composition of Fe₉₀Sc₁₀ in an inert-gas condensation (IGC) process. X-ray diffraction, Moessbauer spectroscopy as well as magnetometric characterization methods were applied to characterize the samples. Magnetometric measurements revealed a significant change of magnetic properties in the Fe rich compound marked by an increase of the Curie point to temperatures well above 300 K, which is much higher than the transition temperature in regular metallic glasses of similar composition. The maximum magnetic hyperfine field obtained from low temperature Moessbauer spectroscopy was about 37.5 T, which is much more than observed in bcc-Fe. This newly identified ferromagnetic phase is attributed to the modified short-range-order in the interfaces of adjacent amorphous nanoparticles.

[en] In this paper we introduce an innovative bottom–up approach for engineering self-assembled magnetic nanostructures using epitaxial strain-induced twinning and phase separation. X-ray diffraction, ⁵⁷Fe Mössbauer spectroscopy, scanning tunneling microscopy, and transmission electron microscopy show that epitaxial films of a near-equiatomic FeRh alloy respond to the applied epitaxial strain by laterally splitting into two structural phases on the nanometer length scale. Most importantly, these two structural phases differ with respect to their magnetic properties, one being paramagnetic and the other ferromagnetic, thus leading to the formation of a patterned magnetic nanostructure. It is argued that the phase separation directly results from the different strain-dependence of the total energy of the two competing phases. This straightforward relation directly enables further tailoring and optimization of the nanostructures’ properties. (paper)

[en] Two members of the pyroxene family, the germanate-type LiFeGe₂O₆ and the titanate-type LiFeTi₂O₆, are prepared for the first time via non-conventional one-step mechanosynthesis. The evolution of the as-prepared materials in the course of mechanosynthesis and their structural state on the long-range and local atomic scales are characterized by X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy, respectively. Both, the nanocrystalline nature of LiFeGe₂O₆ and the nanoglassy state of LiFeTi₂O₆ are revealed.

[en] This article describes a detailed investigation of the crystallographic and magnetic structure of perovskite type Ba₃Fe₃O₇F by a combined analysis of X-ray and neutron powder diffraction data. Complete ordering of vacancies within the perovskite lattice could be confirmed. In addition, the structure of the anion sublattice was studied by means of the valence bond method, which suggested partial ordering of the fluoride ions on two of the six crystallographically different anion sites. Moreover, the compound was found to show G-type antiferromagnetic ordering of Fe moments, in agreement with magnetometric measurements as well as previously recorded ⁵⁷Fe Mössbauer spectroscopy data. - Graphical abstract: The vacancy and anion ordered structure of Ba₃Fe₃O₇F is described together with its magnetic properties. - Highlights: • Ba₃Fe₃O₇F possesses a unique vacancy order not found for other perovskite type compounds. • The valence bond method was used to locate oxide and fluoride ions. • Fluoride ions are distributed only on two of the six anion sites in Ba₃Fe₃O₇F. • The compound shows G-type antiferromagnetic ordering of magnetic moments. • The magnetic structure could be refined in one of the maximal magnetic subgroups of the nuclear structure.