High-Pressure Synthesis and Crystal Growth, Characterization and Thermodynamic Properties of Iron-Pnictide Superconductors and Related Systems

铁磷族超导体及相关系统的高压合成和晶体生长、表征和热力学性质

• 批准号: 168411030
• 负责人: Professor Dr. Michael Lang, since 2/2013
• 金额: --
• 依托单位: Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/168411030?language=en
• 关键词: Pressure; Synthesis; Crystal; Growth; Characterization

The focus of this project rests on the synthesis of high-quality samples of Fe-pnictide and related superconductors, and the achievement of a detailed understanding of their structural, magnetic and superconducting properties. Special emphasis will be placed on high-pressure synthesis – a promising technique for obtaining high-Tc materials in this class of superconductors -, and highest-resolution thermodynamic studies, such as specific heat, thermal expansion and ultrasound propagation. The latter two techniques as well as resistivity measurements can be combined with hydrostatic (4He-gas) pressure. To reach these goals, we will proceed along to main lines, which are closely interconnected: i) Ambient- and high-pressure (AP/HP) synthesis as well as crystal growth; ii) Material characterization as well as thermodynamic and transport measurements at ambient and hydrostatic pressure on selected compounds. In i) the aim is to synthesize monophasic samples of LnFeAsO1-x Fy (Ln = La, Ce, Tb and Dy) at HP/high-temperature (HT) conditions; AP- and HP-crystal growth of AeFe2As2 (Ae = Ca, Ba) and their doped variants and samples of FeSe1-x both at AP- and HP-conditions. In ii), the structural and physical characterization will be performed by employing standard techniques, such as X-ray diffraction, resistivity and magnetic measurements. These results are indispensable input parameters for optimizing the synthesis conditions in i). Detailed studies of their thermodynamic properties will be carried out on selected high-quality materials. In particular, since the HP preparation will affect the structural, magnetic and superconducting properties differently, these studies aim at gaining a deeper insight into the mutual interplay of these properties.

该项目的重点在于合成高质量的铁磷属元素化物和相关超导体样品，并详细了解其结构，磁性和超导特性。特别强调将放在高压合成-一个有前途的技术，获得高Tc材料在这类超导体-和最高分辨率的热力学研究，如比热，热膨胀和超声传播。后两种技术以及电阻率测量可以与流体静压（4 He气体）结合。为了实现这些目标，我们将继续沿着主线，这是密切相关的：i）环境和高压（AP/HP）合成以及晶体生长; ii）材料表征以及在环境和静水压力下对选定的化合物进行热力学和输运测量。在i）中，目的是在HP/高温（HT）条件下合成LnFeAsO 1-xFy（Ln = La、Ce、Tb和Dy）的单相样品;在AP和HP条件下AP和HP晶体生长AeFe 2As 2（Ae = Ca、Ba）及其掺杂变体和FeSe 1-x样品。在ii）中，将采用标准技术（如X射线衍射、电阻率和磁性测量）进行结构和物理表征。这些结果对于优化i）中的合成条件是不可缺少的输入参数。将对选定的高质量材料进行热力学性质的详细研究。特别是，由于HP制备会对结构、磁性和超导性质产生不同的影响，因此这些研究旨在更深入地了解这些性质的相互作用。