共查询到16条相似文献,搜索用时 125 毫秒
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用液氮骤冷方法制备了(AgI)_x(Ag_4P_2O_r)_(1-x)系列非晶态快离子导体。对AgI摩尔浓度x=0.50,0.60,0.67,0.75,0.80的样品,在77—300K温度范围及2,5,10,15MHz的频率上测量了纵波和横波的超声衰减和声速。发现在200—240K附近存在一个异常强的弛豫型超声吸收峰,随AgI含量的增加,该峰的位置向低温方向移动,且峰的高度增大。在实验的温度范围内,观察到纵波和横波的内耗Q_M~(-1)基本相等。由声速与AgI浓度关系的实验结果,计算了样品的弹性常数,并分析了玻璃态结构的变化。 用Ngai提出的低频涨落、耗散和弛豫过程的统一理论(即红外发散响应(IDR)理论),对实验结果进行了较满意的解释,给出了样品的表观激活能和红外发散指数。 相似文献
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由中国科学院数理学部和中国物理学会联合主办的第四届全国非晶态材料和物理学术讨论会于1985年5月9日至13日在西安市举行.来自全国70多个单位的220余名代表参加了会议.会上就非晶态半导体物理、工艺和物性,非晶态金属的结构,结构弛豫和稳定性,工艺和应用,基础物性及其它等方面内容,分五个学术组交流了约二百篇论文.并就非晶硅、微晶硅研究的现状和展望,国内、外非晶态金属薄带和薄膜的研究和应用,某些非晶态合金的原子和电子结构,金属玻璃的内耗以及非晶态快离子导体等方面组织了16篇专题报告,对普遍感兴趣的问题还组织了专题讨论会.美国从… 相似文献
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本文将红外发散响应理论应用到集团自旋玻璃体系中磁集团取向变化弛豫过程,研究自旋玻璃体系(COF_7)_(0.5)(BaF_2)_(0.2)(NaPO_3)_(0.3)的低温超声吸收特性。结果表明T<4.0K时,超声吸收的磁贡献部分主要来自于磁集团的集体转向弛豫过程;T>4.0K时,超声吸收的磁贡献部分是集团集体转向过程和集团内部贡献的迭加。 相似文献
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K. Y. Szeto 《Hyperfine Interactions》1986,31(1-4):87-92
A theory is developed for the calculation of zero field muon spin relaxation function for classical simple magnets (Ising,
XY, and Heisenberg) in D(=1,2,3) dimensions. The results are different from the Kubo-Toyabe theory, except for Heisenberg
system in three dimension. Relation between the relaxation function and random field distribution is dicussed and a new method
of analysing experimental data is suggested and discussed in the context of spin glasses. 相似文献
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By measuring the nuclear spin-lattice relaxation time of 127I cooperative effects in Ag diffusion have been found which point to the necessity to include mutual cation interaction in the diffusion theory. An anomalous increase of the relaxation rate within 5 K just below the transition into the superionic state is taken as dynamical evidence for a discontinuity in the number of diffusing Ag ions, i.e. for sublattice melting. 相似文献
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E. A. Bychkov Yu. V. Ganzha Yu. S. Grushko M. F. Kovalev L. I. Molkanov Yu. G. Vlasov G. Wortmann 《Hyperfine Interactions》1990,55(1-4):921-925
129I-Mössbauer spectroscopy was used to study the short-range order in I-containing chalcogenide glasses. It was found that AsXI glasses, where X=S or Se, are molecular solids composed from molecular units of arsenic iodide and arsenic chalcogenide. The local environment of iodide ions in ternary superionic conducting glasses AgI?Ag2S?As2S3 is similar to that in the crystalline superionic conductor Ag3SI and differs distinctly from iodide local order in binary vitreous alloys AgI?As2S3 and crystalline AgI.129I-Mössbauer spectra of all glasses were fitted satisfactory, when a distribution of the electric-quadrupole coupling constant is taken into account. 相似文献
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An overview is presented of the phase changes as well as certain relaxation characteristics of model quantum magnets, magnetic glasses and proton glasses. Although the systems considered are quite varied, they are connected by the common themes of tunneling, transverse Ising model, long-ranged interactions and above all, the occurrence of quantum phase transitions. Because the interactions are long-ranged, mean-field theory is eminently suitable for analyzing both the equilibrium and nonequilibrium properties. Wherever pertinent, detailed comparisons with experimental data have been presented. 相似文献
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Understanding mechanical relaxation, such as primary(α) and secondary(β) relaxation, is key to unravel the intertwined relation between the atomic dynamics and non-equilibrium thermodynamics in metallic glasses. At a fundamental level, relaxation, plastic deformation, glass transition, and crystallization of metallic glasses are intimately linked to each other, which can be related to atomic packing, inter-atomic diffusion, and cooperative atom movement. Conceptually, βrelaxation is usually associated with structural heterogeneities intrinsic to metallic glasses. However, the details of such structural heterogeneities, being masked by the meta-stable disordered long-range structure, are yet to be understood. In this paper, we briefly review the recent experimental and simulation results that were attempted to elucidate structural heterogeneities in metallic glasses within the framework of β relaxation. In particular, we will discuss the correlation amongβ relaxation, structural heterogeneity, and mechanical properties of metallic glasses. 相似文献