Condensed Matter Research using Intense Spallation Neutrons

日本和英国在中子散射方面的合作是日本国家高能物理实验室(KEK)和英国科学与工程研究委员会(SERC)于1986年建立的一项协议的结果，该协议旨在促进日本和英国科学家在脉冲中子散射领域的科学合作和交流。它导致了ISIS设施的MARI光谱仪的建造，并使日本科学家能够正式进入ISIS的科学计划。在1996财政年度，特别强调了特定科学领域的进展，如无序系统的动力学性质，低维磁体的量子效应，高温超导体中的磁和原子激发等。日本和英国在1996财政年度的合作的一些科学成就的亮点如下：(1)近几年来，动力Pr…受到了相当大的关注呈现出分形几何的高度分叉的渗流网络的更多操作。利用高能分辨中子实验，首次在磁场浓度接近渗流阈值的RbMn；&lt；0.39&gt；mg_&lt；0.61&gt；F_3中观察到了从长波自旋波激发到短波分子激发的交叉现象。(2)为了解决低维磁性系统中各种量子效应的起源，世界各地的许多研究人员正在积极开展工作。目前这一领域的一个问题是自旋梯形系统中的磁激发。在S=1/2SrCu2O3二阶梯体系中发现了能隙，这表明二支梯体系的基态为单重态。(3)除上述结果外，我们还获得了许多成功的实验结果，包括非晶态金属体系中的原子振动，氢键化合物中的相变机制，高温超导体YBa2Cu3O7中的高能磁激发。

The Japan-UK Collaboration in Neutron Scattering is a consequence of an Agreement between the Japanese National Laboratory for High Energy Physics (KEK) and UK Science and Engineering Research Council (SERC) established in 1986 to promote scientific collaboration and interchange between Japanese and UK scientists in the field of pulsed neutron scattering. It has resulted in the construction of the MARI spectrometer at the ISIS Facility and has given formal access to the scientific program at ISIS for Japanese scientists.In the fiscal year of 1996, a special emphasis was placed on the progress of specific scientific fields such as dynamical properties of disordered systems, quantum effects in low-dimensional magnets, magnetic and atomic excitations in high-temperature superconductors, etc.Some highlights of scientific achievements of the Japan-UK Collaboration in the fiscal year of 1996 are as follows.(1) In recent years, considerable attention has been directed towards the dynamical pr … More operties of highly ramified percolating networks that exhibit a fractal geometry. With high energy-resolution neutron experiments, a crossover from long-wavelength spin-wave excitations to short-wavelength fracton excitations in RbMn_<0.39>Mg_<0.61>F_3, whose magnetic concentration is close to the percolation threshold, was observed for the first time.(2) In order to resolve the origin of various quatum effects in low-dimensional magnetic systems, many researchers around the world are working actively. One of the current problems in this field is magnetic excitations in spin ladder systems. We have found energy gap in a two-leg ladder system with S=1/2, SrCu_2O_3. This suggests that ground state of 2-leg ladder system is singlet.(3) Besides of above results, we have obtained many successful experimental results including atomic vibration in amorphous metallic systems, phase transition mechanism in hydrogen-bonded compounds, high-energy magnetic excitations in high-temperature superconductor YBa_2Cu_3O_7. Less