RUI: Physics of 2D and 3D Perovskites

9705155 Oseroff我们将对二维和三维钙钛矿进行系统的研究。第一部分是Sr和Li掺杂La2NiO4和La2CuO4的研究，主要通过电子自旋共振（ESR）进行。Li+在平面上形成一个洞，这个洞似乎是局部的。这项工作提供了将具有平面内孔的系统与通过平面外替换引入的具有移动孔的系统进行比较的可能性。第二部分与钙钛矿型锰酸盐R1-xBxMnO3具有（R=La， Pr等，B = Ca， Sr等）的巨大磁阻响应有关。我们将进行：a) Tc和高t之间的ESR研究；b) Lal-xCaxMnO3+ 20 nm至100 nm的小颗粒研究；c)稀释体系（如LaScO3+: Mn）的测量。这项研究将为这些系统的潜在物理学提供新的见解，并有望产生更好的理论模型。1986年，Bednorz和Muller发现掺杂La2CuO4成为高温超导体（HTS）。从那时起，大量的实验学家和理论家做出了巨大的努力来理解高温超导的起源。尽管作出了巨大努力，但尚未达成共识。我们将对已经报告的数据进行系统的分析。这与一些精心挑选的实验相结合，应该有助于我们理解这些迷人且可能有用的材料的潜在物理原理。接下来，我们将对一个类似家族的成员，掺杂LaMnO3进行测量。这些系统与高温超导材料具有相同的重要特性，并且它们具有通过成为未来的磁传感器来提高存储密度的巨大潜力。* * *

9705155 Oseroff We will perform a systematic research on 2D and 3D perovskites. The first part is a study of La2NiO4 and La2CuO4 doped with Sr and Li, which will be carried out mainly by Electron Spin Resonance, ESR. Li+ brings a hole into the plane and this hole appears to be localized. This work offers the possibility of comparing systems with in- plane holes to those with mobile ones introduced by out-of- plane substitutions. The second part is connected with the huge magnetoresistive response found in the perovskite manganate R1-xBxMnO3 with (R=La, Pr, etc. and B = Ca, Sr, etc.). We will perform: a) An ESR study between Tc and high T. b) Research on small grain size particles of Lal-xCaxMnO3+ from 20 nm to 100 nm. c) Measurements on diluted systems, such as LaScO3+: Mn. This research should provide new insight into the underlying physics of these systems and hopefully lead to better theoretical models. %%% Non-Technical abstract In 1986 Bednorz and Muller discovered that doped La2CuO4 becomes a High Temperature Superconductor, HTS. Since then an enormous effort has been made by a large number of experimentalists and theoreticians to understand the origin of high-temperature superconductivity. In spite of the tremendous efforts made, no consensus has been reached. We are going to carry out a systematic analysis of the data already reported. This, in conjuction with a few well selected experiments, should help us understand the underlying physics of these fascinating and possibly useful materials. We will follow this by carrying out measurements on members of a similar family, doped LaMnO3. These systems share important features with the HTS materials, and they have a great potential for boosting storage density by becoming the magnetic sensors of the future. ***