Collective effects in a random-site electric dipole system: KTaO3: Li
Collective effects in a random-site electric dipole system: KTaO3: Li
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随机位点电偶极子系统中的集体效应：KTaO3：Li
DOI：
10.1103/physrevb.27.89
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发表时间：
1983
影响因子：
3.7
通讯作者：
U. Höchli
中科院分区：
文献类型：
--
作者：
J. J. Klink;D. Rytz;F. Borsa;U. Höchli
Li取代KTa O 3 中的K，由于其相对于立方位点的偏离中心位置而产生局部电偶极子。我们通过核磁共振、介电弛豫、热释电、超声和双折射方法研究了这种具有不同含量Li的晶体（在少数情况下还掺杂Nb，代替Ta）。双折射和介电敏感性结果表明，Li 偶极子之间的集体效应发生在 50 K 数量级的相当明确的浓度依赖性温度以下，但核磁和介电弛豫表明这些效应开始时不存在临界性。这些集体效应与自旋玻璃中产生的集体效应有关。我们根据随机相互作用矩系统的理论模型和计算机模拟来讨论这些数据，这些模型预测了明显的凝聚成一个没有长程有序的亚稳态簇系统。
Li, substituting for K in KTa O 3, creates a local electric dipole, due to its off-center position with respect to the cubic site. We have studied such crystals with different amounts of Li (and in a few cases also doped with Nb, substituting for Ta) by nuclear magnetic resonance, dielectric relaxation, pyroelectricity, ultrasound, and birefringence methods. Birefringence and dielectric susceptibility results show that collective effects between the Li dipoles occur below a fairly well-defined concentration-dependent temperature of the order of 50 K, but nuclear magnetic and dielectric relaxation indicate the absence of criticality at the onset of these effects. These collective effects are related to those arising in spin-glasses. We discuss the data in the light of theoretical models and computer simulations of systems of randomly interacting moments, which predict an apparent condensation into a system of metastable clusters without long-range order.