Electronic and Magnetic Phenomena in Transition Metal Oxides and Hybrid Ferromagnet/Superconductor Nanostructures

过渡金属氧化物和混合铁磁体/超导纳米结构中的电子和磁性现象

• 批准号: 1006606
• 负责人: Carmen Almasan
• 金额: $ 37.5万
• 依托单位: Kent State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1006606&HistoricalAwards=false
• 关键词: Electronic; Magnetic; Phenomena; Transition; Metal

****NON-TECHNICAL ABSTRACT****Two major themes in condensed matter physics are quantum critical phenomena and unconventional superconductivity. A quantum phase transition takes place when quantum matter becomes unstable to a new, ordered ground state. Therefore, quantum criticality is a concept that describes a phase transition between competing ground states driven by an external parameter other than temperature such as chemical composition, pressure, or magnetic field. In principle the phase transition takes place at absolute zero. Nevertheless, a growing body of experimental work indicates that fundamentally new physics can develop over a wide region at finite temperatures. The goal of this research project is to enhance our fundamental understanding of the extent to which quantum criticality controls the finite temperature properties of unconventional superconductors and provide insight into the mutual interplay between unconventional superconductivity and magnetism. The results from these basic investigations are expected to provide further understanding of the interplay between magnetism and superconductivity and to facilitate applications to electronic sensors and devices such as magnetic field sensors or even computer logic devices. This highly interdisciplinary project will allow graduate students and postdocs to benefit from exposure to a diversity of important experimental techniques and a variety of different physical systems and phenomena. The diversity of the expertise gained by the participants in this research program is a substantial advantage in today's knowledge based, technology driven economy, being beneficial to a future career in industry, government, or academia.****TECHNICAL ABSTRACT****This individual investigator award supports a research project addressing major themes in condensed matter physics: quantum criticality and unconventional superconductivity in Fe pnictides, and the interplay between superconductivity and magnetism in pnictides and hybrid ferromagnet/superconductor (F-S) structures. These studies are expected to significantly enhance our fundamental understanding of the extent to which quantum criticality controls the finite temperature properties of unconventional superconductors and promise a deeper insight into the mutual interplay between unconventional superconductivity and magnetism. In addition by comparing and contrasting the Fe-pnictides and cuprates superconductors, the project may contribute to uncovering the vital clues that theorists need to solve the mystery of high-temperature superconductivity. The strong mutual interaction between the ferromagnetic and superconducting subsystems of heterogeneous F-S structures does not suppress either property, but rather can dramatically change the structure and properties of both of them. Therefore these structures offer unlimited possibilities for qualitatively new science and technologies. For example, such structures offer important technological promise for devices whose transport properties can be easily tuned by comparatively weak magnetic fields. This highly interdisciplinary project will allow graduate students and postdocs to benefit from exposure to a diversity of important experimental techniques and a variety of different physical systems and phenomena. The diversity of the expertise gained by the participants in this research program is a substantial advantage in today's knowledge based, technology driven economy, being beneficial to a future career in industry, government, or academia.

**** 非技术摘要 *** 凝聚态物理学的两个主要主题是量子临界现象和非常规超导性。 当量子物质变得不稳定到一个新的、有序的基态时，量子相变就发生了。 因此，量子临界性是一个描述竞争基态之间的相变的概念，该相变由温度以外的外部参数驱动，例如化学成分，压力或磁场。 原则上，相变发生在绝对零度。 然而，越来越多的实验工作表明，新的物理学可以在有限的温度下在广阔的区域内发展。 该研究项目的目标是加强我们对量子临界控制非常规超导体有限温度特性的程度的基本理解，并深入了解非常规超导性和磁性之间的相互作用。 这些基础研究的结果有望进一步了解磁性和超导性之间的相互作用，并促进电子传感器和设备，如磁场传感器，甚至计算机逻辑器件的应用。 这个高度跨学科的项目将使研究生和博士后受益于接触各种重要的实验技术和各种不同的物理系统和现象。 参与者在这项研究计划中获得的专业知识的多样性是当今以知识为基础，技术驱动的经济中的一个重大优势，有利于未来在工业，政府或学术界的职业生涯。技术摘要 **** 该个人研究者奖支持一个解决凝聚态物理学主要主题的研究项目：铁磷属元素化物中的量子临界性和非常规超导性，以及铁磷属元素化物和混合铁磁体/超导体（F-S）结构中超导性和磁性之间的相互作用。 这些研究预计将显着提高我们的量子临界控制非常规超导体的有限温度特性的程度的基本理解，并承诺更深入地了解非常规超导性和磁性之间的相互作用。 此外，通过比较和对比铁磷族化合物和铜酸盐超导体，该项目可能有助于揭示理论家解决高温超导性之谜所需的重要线索。 异质F-S结构中铁磁子系统和超导子系统之间的强相互作用并不抑制任何一种性质，而是可以显著改变它们的结构和性质。 因此，这些结构为新的科学和技术提供了无限的可能性。 例如，这样的结构为器件提供了重要的技术前景，这些器件的输运特性可以通过相对较弱的磁场容易地调节。 这个高度跨学科的项目将使研究生和博士后受益于接触各种重要的实验技术和各种不同的物理系统和现象。 参与者在这项研究计划中获得的专业知识的多样性是当今以知识为基础，技术驱动的经济中的一个重大优势，有利于未来在工业，政府或学术界的职业生涯。

项目成果

Pressure studies of the quantum critical alloy Ce0.93Yb0.07CoIn5

量子临界合金Ce0.93Yb0.07CoIn5的压力研究

• DOI: 10.1103/physrevb.91.174506
• 发表时间: 2015
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Singh, Y. P.;Haney, D. J.;Huang, X. Y.;White, B. D.;Maple, M. B.;Dzero, M.;Almasan, C. C.
• 通讯作者: Almasan, C. C.

Quantum criticality and superconducting pairing in Ce 1-x Yb x CoIn 5 alloys

Ce 1-x Yb x CoIn 5 合金中的量子临界性和超导配对

• DOI: 10.1088/1742-6596/592/1/012078
• 发表时间: 2015
• 期刊: Journal of Physics: Conference Series
• 作者: Singh, Y P;Haney, D J;Lum, I K;White, B D;Maple, M B;Dzero, M;Almasan, C C
• 通讯作者: Almasan, C C