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FeRh attracts intensive interest in antiferromagnetic (AFM) spintronics due to its first-order phase transition between the AFM and ferromagnetic (FM) phase, which is unique for exploring spin dynamics in coexisting phases. Here, we report lateral spin pumping by which angular momentum is transferred from FM domains into the AFM matrix during the phase transition of ultrathin FeRh films. In addition, FeRh is verified to be both an efficient spin generator and an efficient spin sink, by electrically probing vertical spin pumping from FM-FeRh into Pt and from Py into FeRh, respectively. A dramatic enhancement of damping related to AFM-FeRh is observed during the phase transition, which we prove to be dominated by lateral spin pumping across the FM/AFM interface. The discovery of lateral spin pumping provides insight into the spin dynamics of magnetic thin films with mixed-phases, and the significantly modulated damping advances its potential applications, such as ultrafast spintronics. Iron–rhodium is a promising material for antiferromagnetic (AFM) spintronics applications. Here, the authors demonstrate a strong enhancement of damping during the ferromagnetic (FM) to AFM phase transition caused by lateral spin pumping from FM domains to the AFM matrix.

Introduction We used an inducible mouse model expressing the Tau repeat domain with the pro-aggregant mutation ΔK280 to analyze presynaptic Tau pathology in the hippocampus. Results Expression of pro-aggregant Tau RDΔ leads to phosphorylation, aggregation and missorting of Tau in area CA3. To test presynaptic pathophysiology we used electrophysiology in the mossy fiber tract. Synaptic transmission was severely disturbed in pro-aggregant Tau RDΔ and Tau-knockout mice. Long-term depression of the mossy fiber tract failed in pro-aggregant Tau RDΔ mice. We observed an increase in bouton size, but a decline in numbers and presynaptic markers. Both pre-and postsynaptic structural deficits are preventable by inhibition of Tau RDΔ aggregation. Calcium imaging revealed progressive calcium dysregulation in boutons of pro-aggregant Tau RDΔ mice. In N2a cells we observed this even in cells without tangle load, whilst in primary hippocampal neurons transient Tau RDΔ expression alone caused similar Ca ++ dysregulation. Ultrastructural analysis revealed a severe depletion of synaptic vesicles pool in accordance with synaptic transmission impairments. Conclusions We conclude that oligomer formation by Tau RDΔ causes pre- and postsynaptic structural deterioration and Ca ++ dysregulation which leads to synaptic plasticity deficits.

This volume of the Haskins Society Journal brings together a rich and interdisciplinary collection of articles. Topics range from the politics and military organization of northern worlds of the Anglo-Normans and Angevins in the twelfth and thirteenth centuries, to the economic activity of women in Catalonia and political unrest in thirteenth-century Tripoli. Martin Millett's chapter on the significance of rural life in Roman Britain for the early Middle Ages continues the Journal's commitment to archaeological approaches to medieval history, while contributions on Ælfric's complex use of sources in his homilies, Byrhtferth of Ramsey's reinterpretation of the Alfredian past, and the little known History of Alfred of Beverly engage with crucial questions of sources and historiographical production within Anglo-Saxon and Anglo-Norman England. Pieces on the political meaning of the Empress Helena and Constantine I for Angevin political ambitions and the role of relics such as the Holy Lance in strategies of political legitimation in Anglo-Saxon England and Ottonian Germany in the tenth century complete the volume. Contributors: David Bachrach, Mark Blincoe, Katherine Cross, Sarah Ifft Decker, Joyce Hill, Katherine Hodges-Kluck, Jesse Izzo, Martin Millett, John Patrick Slevin, Oliver Stoutner, Laura Wangerin.

We report the experimental observation of spin-orbit torque induced switching of perpendicularly magnetized Pt/Co elements in a time resolved stroboscopic experiment based on high resolution Kerr microscopy. Magnetization dynamics is induced by injecting sub-nanosecond current pulses into the bilayer while simultaneously applying static in-plane magnetic bias fields. Highly reproducible homogeneous switching on time scales of several tens of nanoseconds is observed. Our findings can be corroborated using micromagnetic modelling only when including a field-like torque term as well as the Dzyaloshinskii-Moriya interaction mediated by finite temperature.

Ultrafast electron delocalization induced by a fs laser pulse is a well-known process and is the initial step for important applications such as fragmentation of molecules or laser ablation in solids. It is well understood that an intense fs laser pulse can remove several electrons from an atom within its pulse duration. [1] However, the speed of electron localization out of an electron gas, the capture of an electron by ion, is unknown. Here, we demonstrate that electronic localization out of the conduction band can occur within only a few hundred femtoseconds. This ultrafast electron localization into 4f states has been directly quantified by transient x-ray absorption spectroscopy following photo-excitation of a Eu based correlated metal with a fs laser pulse. Our x-ray experiments show that the driving force for this process is either an ultrafast reduction of the energy of the 4f states, a change of their bandwidth or an increase of the hybridization between the 4f and the 3d states. The observed ultrafast electron localization process raises further basic questions for our understanding of electron correlations and their coupling to the lattice.

Magnonics, i.e. the artificial manipulation of spin waves, is a flourishing field of research with many potential uses in data processing within reach. Apart from the technological applications the possibility to directly influence and observe these types of waves is of great interest for fundamental research. Guidance and steering of spin waves has been previously shown and lateral spin wave confinement has been achieved. However, true spin wave focusing with both lateral confinement and increase in amplitude has not been shown before. Here, we show for the first time spin wave focusing by realizing a Fresnel zone plate type lens. Using x-ray microscopy we are able to directly image the propagation of spin waves into the nanometer sized focal spot. Furthermore, we observe that the focal spot can be freely moved in a large area by small variations of the bias field. Thus, this type of lens provides a steerable intense nanometer sized spin wave source. Potentially, this could be used to selectively illuminate magnonic devices like nano oscillators with a steerable spin wave beam.

We report the experimental observation of Snell's law for magneto-static spin waves in thin ferromagnetic Permalloy films by imaging incident, refracted and reflected waves. We use a thickness step as the interface between two media with different dispersion relation. Since the dispersion relation for magneto-static waves in thin ferromagnetic films is anisotropic, deviations from the isotropic Snell's law known in optics are observed for incidence angles larger than 25 with respect to the interface normal between the two magnetic media. Furthermore, we can show that the thickness step modifies the wavelength and the amplitude of the incident waves. Our findings open up a new way of spin wave steering for magnonic applications.