Magnetic coupling in highly-ordered NiO/Fe3O4(110): Ultrasharp magnetic interfaces vs. long-range magnetoelastic interactions

We present a laterally resolved X-ray magnetic dichroism study of the magnetic proximity effect in a highly ordered oxide system, i.e. NiO films on Fe3O4(110). We found that the magnetic interface shows an ultrasharp electronic, magnetic and structural transition from the ferrimagnet to the antiferromagnet. The monolayer which forms the interface reconstructs to NiFe2O4 and exhibits an enhanced Fe and Ni orbital moment, possibly caused by bonding anisotropy or electronic interaction between Fe and Ni cations. The absence of spin-flop coupling for this crystallographic orientation can be explained by a structurally uncompensated interface and additional magnetoelastic effects

Strengthening the impact of the Inter-American Human Rights System through scholarly research: reflective report

This Report contains the collective findings of the Inter-American Human Rights Network, a multi-disciplinary group of international scholars of the Inter-American Human Rights System (IAHRS) brought together to gain richer insights into three sets of issues with particular salience for the IAHRS: compliance and impact; the politics and practice of institutional and legal change; and cross-regional perspectives on human rights systems

Prediction of huge X-ray Faraday rotation at the Gd N_4,5 threshold

X-ray absorption spectra in a wide energy range around the 4d-4f excitation threshold of Gd were recorded by total electron yield from in-plane magnetized Gd metal films. Matching the experimental spectra to tabulated absorption data reveals unprecedented short light absorption lengths down to 3 nm. The associated real parts of the refractive index for circularly polarized light propagating parallel or antiparallel to the Gd magnetization, determined through the Kramers-Kronig transformation, correspond to a magneto-optical Faraday rotation of 0.7 degrees per atomic layer. This finding shall allow the study of magnetic structure and magnetization dynamics of lanthanide elements in nanosize systems and dilute alloys.Comment: 4 pages, 2 figures, final version resubmitted to Phys. Rev. B, Brief Reports. Minor change

Magnetic versus crystal field linear dichroism in NiO thin films

We have detected strong dichroism in the Ni $L_{2,3}$ x-ray absorption spectra of monolayer NiO films. The dichroic signal appears to be very similar to the magnetic linear dichroism observed for thicker antiferromagnetic NiO films. A detailed experimental and theoretical analysis reveals, however, that the dichroism is caused by crystal field effects in the monolayer films, which is a non trivial effect because the high spin Ni $3d^{8}$ ground state is not split by low symmetry crystal fields. We present a practical experimental method for identifying the independent magnetic and crystal field contributions to the linear dichroic signal in spectra of NiO films with arbitrary thicknesses and lattice strains. Our findings are also directly relevant for high spin $3d^{5}$ and $3d^{3}$ systems such as LaFeO$_{3}$, Fe$_{2}$O$_{3}$, VO, LaCrO$_{3}$, Cr$_{2}$O$_{3}$, and Mn$^{4+}$ manganate thin films

Remembering the ‘unwanted’ victims: initiatives to memorialize the National Socialist euthanasia program in Germany

Between 1939 and 1945, approximately 200,000 patients were murdered under the National Socialist euthanasia program in Germany and Austria. For many years, these victims were largely excluded from post-war commemorative culture and they are yet to attain legal equality with the victims of political or racial persecution. This article considers recent initiatives to commemorate the victims of euthanasia, focusing on three examples: 1) the national memorial and information point for the victims of National Socialist “euthanasia” killings in Berlin; 2) the web portal http://www.gedenkort-t4.eu” www.gedenkort-t4.eu; and 3) the national competition “Andersartig Gedenken”, which invited young Germans to design their own memorial

Introduction: Rethinking the Impact of the Inter-American Human Rights System

This chapter introduces the central themes of the book and argues that the Inter-American Human Rights System (IAHRS) is activated by political actors and institutions in ways that transcend traditional compliance perspectives and that have the potential to meaningfully alter politics and provoke positive domestic human rights change. The chapter identifies key gaps in existing human rights scholarship, particularly in relation to the IAHRS, and outlines three core perspectives on the System’s impact on human rights. It offers a synthesis of the key findings of the volume, and provides reflections on the future prospects of the System by locating it in its broader global context

ABSTRACTS OF PRESENTATIONS

Second International Conference on African Digital Libraries and Archives, abstracts of presentation

Li14Ln5[Si11N19O5]O2F2 with Ln = Ce, Nd-Representatives of a Family of Potential Lithium Ion Conductors

The isotypic layered oxonitridosilicates Li14Ln5[Si11N19O5]O2F2 (Ln = Ce, Nd) have been synthesized using Li as fluxing agent and crystallize in the orthorhombic space group Pmmn (Z = 2, Li14Ce5[Si11N19O5]O2F2: a = 17.178(3), b = 7.6500(15), c = 10.116(2) Å, R1 = 0.0409, wR2 = 0.0896; Li14Nd5 Si11N19O5]O2F2: a = 17.126(2), b = 7.6155 15), c = 10.123(2) Å, R1 = 0.0419, wR2 = 0.0929). The silicate layers consist of dreier and sechser rings interconnected via common corners, yielding an unprecedented silicate substructure. A topostructural analysis indicates possible 1D ion migration pathways between five crystallographic independent Li positions. The specific Li-ionic conductivity and its temperature dependence were determined by impedance spectroscopy as well as DC polarization/depolarization measurements. The ionic conductivity is on the order of 5 × 10−5 S/cm at 300°C, while the activation energy is 0.69 eV. Further adjustments of the defect chemistry (e.g., through doping)can make these compounds interesting candidates for novel oxonitridosilicate based ion conductors