[en] Spin ice is a geometrically frustrated magnetic system possessing pyrochlore lattice structure, with magnetic moments residing on the vertices of the corner-sharing tetrahedral network, and obeying the two-in two-out ice-rule Ising interactions as analogous to the water ice. The excited states of spin ice can be modeled as emergent magnetic monopoles. While a system with the additional transverse magnetic correlations to the Ising Hamiltonian term, quantum spin ice is nominated. In this talk, I will introduce our studies of the classical spin ice and quantum spin ice by using neutron scattering, μSR, and other techniques.

[en] The meeting will provide physicists, chemists, biologists, engineers, geologists, materials scientists and others the opportunity to discuss to share and discuss their research findings as well as the latest developments in Neutron Scatteringtechniques. AOCNS' facilities in Asia-Oceania.

[en] A national facility for neutron beam research is operated at the research reactor Dhruva in BARC. It includes single-crystal and powder diffractometers, a polarization analysis spectrometer, inelastic and quasi-elastic scattering spectrometers in the reactor hall, and smallangle scattering instruments and a polarized neutron reflectometer in the neutron-guide laboratory. The National facility is utilized in collaboration with various universities and other institutions. The talk will present our facilities and discuss examples of recent work.

[en] Membrane formation is often listed as one of the key steps in the origins of life on this planet, since this enabled the first organisms a certain control over the environment around their genetic material. Unilamellar liposomes are one of the simplest models available of cellular membranes, and small angle neutron scattering is an effective technique to characterize their structure. Bacterial and eukaryotic cells differ in their lipid composition, notably in an increase in charged lipids for bacterial membranes. We are currently studying charged and uncharged liposomes.

[en] Removing the contamination of high order neutrons from the pyrolytic graphite (PG) monochromator is one of the most critical procedures to obtain reliable data on a thermal tripleaxis spectrometer (TAS). This is typically done by putting a PG filter after the sample in the fixed-Ef configuration, which results in many restrictions in the experiments. We have built the Bamboo thermal TAS at China Advanced Research Reactor (CARR), Beijng, China. By installing a neutron velocity selector before the PG monochromator, the incident neutrons are free of unwanted higher neutrons. It allows us to continuously fine tune the energy and momentum resolution in a simple manner. In addition, it provides much more choices in an experiment that may significantly improve the data quality.

[en] Controlling the structure of the active film in organic optoelectronic devices plays an important role in optimising their performance. Neutron techniques such as neutron reflectometry and small angle Neutron Scatteringare important methods for studying the physical structures of (macro)molecules and their interactions non-destructively in solution and/or the solid state. In this presentation we will illustrate how Neutron Scatteringmeasurements can be utilized to elucidate the structure of thin films typically used in organic photovoltaic devices. The presentation will focus on bulk heterojunction thin films comprised of conjugated polymer:fullerene blends. We will also show how time resolved measurements can be used to follow the evolution of the film structure during post-deposition processing. Finally, the structure of the films will be correlated to device performance.

[en] Neutron diffraction technique is the only nondestructive method to map 3-D residual stress field in bulk component, which can help to improve the manufacturing quality of engineering components and to optimise design criteria in applications. Because of its great potential in industrial application, a new residual stress diffractometer at CARR is being built by CIAE and CNU. Its overall optics was designed and optimised by simulation using McStas and SIMRES software. It will be equipped with double focusing Si(400) monochromator, heavy weighted sample stage, large area Detector and two-layer wedges that open the shielding, which will make this instrument to be one of the best neutron stress diffractometers in the world. Also this diffractometer will be qualified with the function of texture measurement.

[en] The Laue diffractometer, KOALA, at the Bragg Institute offers the capability to measure large portions of reciprocal space in a single image. The data reduction process is handled by an inhouse programme, LaueG, developed from the precursor programme, LaueGEN, from the 1980’s. Given the lattice parameters of the sample and a space group, LaueG can be used to treat the Bragg reflections, generating an hkl file for use in an analysis programme. We present here the data treatment process using LaueG in order to minimise R-factors in the hkl file, and the data analysis process that turns this hkl file into a structure. To facilitate the discussion we will use the example of a Cu2ZnSnS4 sample which has site defects at the Cu and Zn positions, and for data analysis, the free-to-use software, Crystals.

[en] The aggregation states of polystyrene (PS) thin films at interfaces with non-solvents such as water, methanol and hexane were examined by specular neutron reflectivity and sum-frequency generation vibrational spectroscopy. The density profiles of the PS thin films along the direction normal to the interface with water and methanol were comparable to that in air. However, this was not the case of the film in hexane exhibiting a diffused interfacial layer due to swelling. Also, the local conformation of PS at the outermost region of the films was quite sensitive to the surrounding environment and responded consequently to a change in its environment. This was the case for typical non-solvents such as water and methanol. The extent of the conformational change might be explained in terms of the interfacial energy. Similar experiments are also performed for poly(methyl methacrylate) (PMMA). Results so obtained are compared with each other.

[en] Spin dynamics of two structurally similar spin-1/2 distorted kagome lattice antiferromagnets Cs2Cu3SnF12 and Rb2Cu3SnF12 will be discussed. Magnetic excitations in Cs2Cu3SnF12, which has an ordered ground state owing to strong Dzyaloshinskii-Moriya interactions, can be qualitatively described by linear spin-wave theory. However, we found that the excitation energies are renormalized by a factor of approximately 0.6. This negative renormalization is attributed to quantum fluctuations, and is in contrast to the positive quantum renormalization observed in a quantum-spin chain. On the other hand, magnetic excitations in Rb2Cu3SnF12, whose ground state is a “pinwheel” valence-bond solid state, can be understood in terms of singlet-to-triplet excitations. Recent high-intensity pulsed neutron scattering reveals a weak dispersive and “ghost” mode, which is attributed to an enlarged unit cell below a structural transition. We also observed continuum scattering at high energy, which is probably reminiscent of the fractionalized excitations recently observed in herbertsmithite. In addition, fielddependence of the singlet-to-triplet excitations will be discussed.