Investigations of Unconventional Superconducting and Magnetic Order-Parameters in Heavy Electron Materials

将研究一类由稀土和锕系元素组成的新型金属间化合物的超导性和磁性。在这些材料中，低温行为主要由电子之间的相互作用决定。将使用一些先进的仪器和技术，如超声波、超导量子干涉装置以及扫描磁强计和输运测量。测量将在高质量的单晶和薄膜样品上进行。极端的物理条件，如高单轴压力、高磁场和极低的温度，将被适当地选择来阐明这些材料中超导性和磁性的独特性质。为此，将使用一种特殊的低温装置，该装置的单轴压力可达8000个大气压，磁场强度接近地球磁场的100万倍。所获得的结果将与材料科学的许多领域有关，包括高温超导，磁存储，强磁场材料等。%%%将用超声波，力以及SQUID磁强计（宏观和微观）和输运测量来研究稀土和锕系金属间重费米子化合物的超导和磁相。这些测量将在高质量的单晶以及薄膜样品上进行。将酌情选择高单轴压力、高磁场和超低温的实验组合来阐明这些材料中的新型超导和磁性现象。这些现象包括(i)超导和磁性的共存，（ii）超导状态下的多阶参数，（i ii）半量子循环的磁场漩涡，（iv）非尼尔型有序的磁性，以及(v)由于界面的存在而产生的新型磁性和输运效应。测量将利用一种特殊的超低温装置，在这种装置中，外部施加的微扰的大小和相互方向、高达8千巴的单轴压力和高达16特斯拉的磁场，都可以在原位控制。＊＊＊

9624468 Shivaram The superconducting and magnetic properties of a new class of intermetallic compounds formed from rare earth and actinide elements will be investigated. In these materials, the low temperature behavior is dominated by the interactions between the electrons. A number of advanced instrumentation and techniques such as ultrasonics, superconducting quantum interference devices as well as scanning magnetometry, and transport measurements will be used. The measurements will be performed on high quality single crystals as well as on thin film samples. Extreme physical conditions such as high uniaxial pressures, high magnetic fields and very low temperatures will be chosen as appropriate to elucidate the unique nature of superconductivity and magnetism in these materials. For this purpose a special low temperature apparatus where uniaxial pressure up to 8,000 atmosphere and magnetic fields close to a million times stronger than the earth's magnetic filed, will be utilized. The results obtained will be relevant to many areas in materials science including high temperature superconductivity, magnetic storage, high field magnetic materials etc. %%% The superconducting and magnetic phases of rare earth and actinide based intermetallic heavy fermion compounds will be investigated with ultrasonics, force as well as SQUID magnetometry (both macroscopic and microscopic) and transport measurements. These measurements will be performed on high quality single crystals as well as on thin film samples. A combination of experiments involving high uniaxial pressures, high magnetic fields and ultra-low temperatures will be chosen as appropriate to elucidate the novel superconducting and magnetic phenomena in these materials. These phenomena include (i) coexistence of superconductivity and magnetism, (ii) multiple order parameters in the superconducting state, (i ii) magnetic filed vortices with half a quantum of circulation, (iv) magnetism with non-Neel types of order, and (v) novel magnetic and transport effects due to the presence of interfaces. The measurements will utilize a special ultra low temperature apparatus where the magnitude and the mutual orientations of externally applied perturbations, uniaxial pressures upto 8 kbar and magnetic fields upto 16 tesla, can be controlled in situ. ***