Condensed Matter Research using Intense Spallation Neutrons

日本-英国中子散射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理事会（SERC）于1986年建立的协议的结果，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。在1996财政年度，特别强调了具体科学领域的进展，如无序系统的动力学性质、低维磁体中的量子效应、高温超导体中的磁和原子激发、以下是1996财政年度日英合作的一些主要科学成就。(1)近年来，人们对动力学过程给予了相当大的关注， ...更多信息 具有分形几何结构的高度分枝的扩张网络的操作。利用高能量分辨中子实验，首次在磁浓度接近逾渗阈值的RbMn_ Mg_ F_3中观察到了从长波自旋波激发到短波分形子激发的跃迁<0.39><0.61>。(2)为了解决低维磁系统中各种量子效应的起源问题，国内外许多学者都在积极地开展工作。目前该领域的一个问题是自旋梯系统中的磁激发。我们在S=1/2SrCu_2O_3的两腿梯形系统中发现了能隙。这表明二腿梯形体系的基态是单线态。(3)除上述结果外，我们还获得了许多成功的实验结果，包括非晶态金属系统中的原子振动，氢键化合物中的相变机制，高温超导体YBa_2Cu_3O_7中的高能磁激发。少

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