Abnormal aggregation of lens protein, α-crystallin, has been observed with in situ small-angle neutron scattering under external stresses. Alpha-crystallin is a complex consisting of 40 subunits: there are two kinds of subunits, αA-crystallin and αB-crystallin. Single aggregate of αA-crystallin made structural deformation by temperature jump to the low temperature but did not by UV irradiation. On the other hand, that of αB-crystallin exhibited opposite response. These results suggested that α-crystallin could obtain tolerant against both external stresses by consisting of αA-crystallin and αB-crystallin. This assumption is also supported by another experimental result that the recombinant complex with αA-crystallin and αB-crystallin did not make the structural deformation by UV irradiation
Microscopic magnetism and dielectric properties in the multiferroic rare-earth manganites of RMn2O5 studied by neutron diffraction and dielectric measurements are reviewed.It has been revealed that RMn2O5 shows successive dielectric and magnetic phase transitions, which concomitantly take place and are induced by temperature, magnetic field, and hydrostatic pressure.This coexistence and mutual coupling between dielectric and magnetic order, as well as the induced 4f magnetic moment on rare-earth ions, are ingredients essential for realizing a rich variety of colossal magnetoelectric effect.
Recent studies of crystalline materials by the atomic pair distribution function (PDF) analysis are introduced.Wide Q-range of diffraction patterns obtained by total scattering diffractometers at intense pulsed neutron facilities such as Materials and Life Science Facility in J-PARC are suitable for the PDF analysis, where high Q-resolution measurement can also be carried out simultaneously. One of the novel research topics is the size and the form of nano-structured materials. Another is local lattice distortion in a functional material, i. e., a giant negative thermal expansion material Mn3Cu1-xGexN.
A hybrid-anvil device was newly developed for high-pressure single-crystal magnetic neutron diffraction experiments up to 10 GPa. The device is composed of a large sapphire anvil and a tungsten carbide (WC) anvil that has a hollow in the center of the culet. In a feasibility test of the device, the maximum pressure of 7 GPa was generated with high stability. The hydrostaticity of pressure-transmitting media, which is essential for the single-crystal diffraction experiments, was investigated by evaluating the mosaic spread of NaCl single crystals under pressure. It was found that glycerin transmits the nearly hydrostatic pressure even at 7 GPa. Using the hybrid-anvil device, single-crystal magnetic neutron diffraction experiments on valence transition material YbInCu4 were performed up to 6.2 GPa. In spite of the small magnetic moment of less than 1μB/Yb, distinct magnetic signals were observed. This was accomplished by using the thermal neutron focusing device with the hybrid-anvil device.
This article reports the present condition and recent topics of neutron powder diffractometers, which located on Japan Research Reactor 3 at Tokai. Furthermore, we report activities of user's meeting. In this meeting, we have discussed a future vision for powder diffractometers on the Research Reactor.
In this series of introductory articles, we give an introduction to the principles and interpretation procedure of neutron reflectivity (NR) as well as applications of NR to various thin films, especially focusing on buried interfaces. For further technical details see the each article.
Neutron reflectometry is a non-destructive structural analysis method utilizing optical property of neutron at interfaces between two media, and is indispensable for structural analysis on material interfaces due to high depth resolution of a sub-nm scale. The specular reflection of neutron at the interface can be described by the Shrodinger equation with the one-dimensional square well potential for a plane wave. Here, the principles of neutron reflectometry are explained using a typical few examples from a single ideal interface to a multi-layer system. Further, the removal of incoherent scattering background by using a polarized neutron beam is explained for hydrogenous materials.