Nonlinear Ultrafast Spin Scattering in the Skyrmion Phase of Cu_{2}OSeO_{3}.

Ultrafast x-ray scattering studies of the topological Skyrmion phase in Cu_{2}OSeO_{3} show the dynamics to be strongly dependent on the excitation energy and fluence. At high photon energies, where the electron-spin scattering cross section is relatively high, the excitation of the topological Skyrmion phase shows a nonlinear dependence on the excitation fluence, in contrast to the excitation of the conical phase which is linearly dependent on the excitation fluence. The excitation of the Skyrmion order parameter is nonlinear in the magnetic excitation resulting from scattering during electron-hole recombination, indicating different dominant scattering processes in the conical and Skyrmion phases.

Selective interlayer ferromagnetic coupling between the Cu spins in YBa2Cu3O7-x grown on top of La0.7Ca0.3MnO3.

Studies to date on ferromagnet/d-wave superconductor heterostructures focus mainly on the effects at or near the interfaces while the response of bulk properties to heterostructuring is overlooked. Here we use resonant soft x-ray scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between the in-plane Cu spins in YBa2Cu3O7-x (YBCO) superconductor when it is grown on top of ferromagnetic La0.7Ca0.3MnO3 (LCMO) manganite layer. This coupling, present in both normal and superconducting states of YBCO, is sensitive to the interfacial termination such that it is only observed in bilayers with MnO2 but not with La0.7Ca0.3O interfacial termination. Such contrasting behaviors, we propose, are due to distinct energetic of CuO chain and CuO2 plane at the La0.7Ca0.3O and MnO2 terminated interfaces respectively, therefore influencing the transfer of spin-polarized electrons from manganite to cuprate differently. Our findings suggest that the superconducting/ferromagnetic bilayers with proper interfacial engineering can be good candidates for searching the theorized Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the competing quantum orders in highly correlated electron systems.

Coupled Skyrmion sublattices in Cu(2)OSeO(3).

We report the observation of a Skyrmion lattice in the chiral multiferroic insulator Cu2OSeO3 using Cu L3-edge resonant soft x-ray diffraction. We observe the unexpected existence of two distinct Skyrmion sublattices that arise from inequivalent Cu sites with chemically identical coordination numbers but different magnetically active orbitals. The Skyrmion sublattices are rotated with respect to each other, implying a long wavelength modulation of the lattice. The modulation vector is controlled with an applied magnetic field, associating this moirélike phase with a continuous phase transition. Our findings will open up a new class of science involving manipulation of quantum topological states.

Glass-like recovery of antiferromagnetic spin ordering in a photo-excited manganite Pr0.7Ca0.3MnO3.

Electronic orderings of charges, orbitals and spins are observed in many strongly correlated electron materials, and revealing their dynamics is a critical step toward undertsanding the underlying physics of important emergent phenomena. Here we use time-resolved resonant soft x-ray scattering spectroscopy to probe the dynamics of antiferromagnetic spin ordering in the manganite Pr0.7Ca0.3MnO3 following ultrafast photo-exitation. Our studies reveal a glass-like recovery of the spin ordering and a crossover in the dimensionality of the restoring interaction from quasi-1D at low pump fluence to 3D at high pump fluence. This behavior arises from the metastable state created by photo-excitation, a state characterized by spin disordered metallic droplets within the larger charge- and spin-ordered insulating domains. Comparison with time-resolved resistivity measurements suggests that the collapse of spin ordering is correlated with the insulator-to-metal transition, but the recovery of the insulating phase does not depend on the re-establishment of the spin ordering.

Ferromagnetic enhancement of CE-type spin ordering in (Pr,Ca)MnO3.

We present resonant soft x-ray scattering results from small bandwidth manganites (Pr,Ca)MnO(3), which show that the CE-type spin ordering (SO) at the phase boundary is stabilized only below the canted antiferromagnetic transition temperature and enhanced by ferromagnetism in the macroscopically insulating state (FM-I). Our results reveal the fragility of the CE-type ordering that underpins the colossal magnetoresistance effect in this system, as well as an unexpected cooperative interplay between FM-I and CE-type SO which is in contrast to the competitive interplay between the ferromagnetic metallic state and CE-type ordering.

Observation of ferromagnetic resonance in SrRuO3 by the time-resolved magneto-optical Kerr effect.

We report the observation of ferromagnetic resonance (FMR) in SrRuO3 using the time-resolved magneto-optical Kerr effect. The FMR oscillations in the time-domain appear in response to a sudden, optically induced change in the direction of easy-axis anisotropy. The high FMR frequency, 250 GHz, and large Gilbert damping parameter, alpha approximately 1, are consistent with strong spin-orbit coupling. We find that the parameters associated with the magnetization dynamics, including alpha, have a nonmonotonic temperature dependence, suggestive of a link to the anomalous Hall effect.

Disabled access to information technology--a portable adaptable, multipurpose device.

The technology exists to allow severely physically disabled people to have a far more independent lifestyle than many handicapped people enjoy today. To use an ever increasing range of sophisticated domestic equipment, without special modifications, an individually tailored control system and a universal accessing device are required. A portable multipurpose device allows multiply handicapped, non-speaking people a means of operating a variety of general-purpose or specialized pieces of electronic equipment at home and elsewhere, safely and independently. The device also provides a means of communication through the medium of computer-computer communication over telephone lines and will interface to a powered chair for independent mobility. Various features are provided which are not available from conventional environmental control systems. Through a specialized adjustable multipurpose switch system and a universal control device the handicapped person should be able to enjoy the independence afforded by the intelligent home of the future.

Portable modular transducer system for the measurement of stabilizing forces in TLS-HKA orthoses.

We describe an instrumentation package built for the measurement of stabilizing forces in thoraco-lumbar-sacral-hip-knee-ankle orthoses. The system uses inexpensive and robust transducers mounted on the orthoses. Instrumentation is contained in a back-pack; the associated software package may be used for a wide variety of transducer applications.

The National Library of Medicine's services: initial observations on indexing, interlibrary loan, and reference.

How have the three services-indexing, reference (including history of medicine), and interlibrary loan-been provided throughout the years by NLM, and how have they been used? At the present time of great growth and development, the use of the computer has influenced these services and will continue to figure prominently in plans for the future. NLM's services often have not been well or correctly used by its public, even by librarians. Some of its services, however, need to be provided in more depth and on a higher scale, and they should be publicized more widely. History shows that NLM has been faithful to its basic charge and has gone far beyond it in its service to the medical, educational, and library communities. Medical librarians are most fortunate that such a great national resource exists to provide materials and services to fulfill the needs of their libraries.