Nanostructured hybrids of superconductors and ferromagnets

我们建议研究由铁磁体和超导体的不同组合组成的纳米结构混合系统的电子和磁性。我们的主要目标是了解超导和铁磁性两个竞争顺序之间的相互作用的基本机制，从而阐明铜氧化物高温超导体（HTS）的配对机制。我们还将尝试控制混合系统的属性，并检查它们是否可以在实际应用中使用。为此，我们将研究由铁磁体和超导体以及不同掺杂的高温超导体组成的双层、多层和纳米复合材料的基本性质。将使用的典型材料包括常规超导体，例如Al、Pb、Zn和Nb，HTS铜酸盐YBa 2Cu 3 O 7 - 5（YBCO）、La 2-xSrxCuO 4（LSCO）、La 2-xSrxCuO 4（LBCO）和Bi 2Sr 2CaCu 2 O 8 +5（BSCCO），以及铁磁体SrRuO 3（SRO）、Nd 2Sr 2 MnO 3、Ni、Fe和Fe 3 O 4（磁铁矿）纳米颗粒。我们计划研究邻近和界面效应，自旋电子学现象，涡旋物质，赝能隙和HTS相图的起源，以及与本征磁超导体相比，人工纳米结构多层膜中超导性和磁性之间的相互作用。纳米厚膜、双层膜和多层膜将通过激光烧蚀沉积和溅射来制备。在我们的研究中将采用各种实验技术，包括扫描隧道显微镜和光谱学（STM和STS），磁光学，时间分辨光学和太赫兹光谱，以及高灵敏度的传输和磁性测量。这种局部探针和“宏观”测量的结合将提供一个全面的图片的纳米结构的混合动力车在手。实验的努力，支持的理论研究的基本属性的高温超导体反映在我们的测量，将进行小组在德国（康斯坦茨大学）和以色列（理工学院，巴伊兰大学和希伯来大学）。这四个小组在必要的材料制备、表征和研究技术方面具有互补的、成熟的专门知识。我们期望，我们小组的专业知识和兴趣的重叠和互补领域的良好平衡组合将促进协同合作，并对HTS及其与铁磁体的混合物的物理学产生新的见解。

We propose studying the electronic and magnetic properties of nano-structured hybrid systems consisting of different combinations of ferromagnets and superconductors. Our main goal is to understand the basic mechanism of the interaction between the two competing orders of super-conductivity and ferromagnetism, and thereby elucidate the pairing mechanism of the cuprate high temperature superconductors (HTS). We shall also attempt to control the hybrid systems properties, and check whether they could be utilized in practical applications. For this we shall study the basic properties of bilayers, multilayers and nano-composites consisting of ferromagnets and super-conductors as well as the differently doped HTS. Typical materials that will be used include conventional superconductors such as Al, Pb, Zn and Nb, the HTS cuprates YBa2Cu3O7_s(YBCO), La2_xSrxCuO4 (LSCO), La2_xBaxCuO4 (LBCO), and Bi2Sr2CaCu2O8+5 (BSCCO),and the ferromagnets SrRuO3 (SRO), Nd^Sr^MnOj, Ni, Fe and Fe3O4 (magnetite) nanoparticles. We plan to investigate proximity and interface effects, spintronics phenomena, vortex matter, the pseudogap and the origin of the HTS phase diagram, as well as the interplay between superconductivity and magnetism in artificial nanostructured multilayers in comparison with the intrinsic magneto-superconductors. Nanometer thick films, bilayers and multilayers will be prepared by laser ablation deposition and sputtering. Various experimental techniques will be employed in our studies including scanning tunneling microscopy and spectroscopy (STM and STS), magneto-optics, time resolved optical and THz spectroscopy, and high sensitivity transport and magnetic measurements. This combination of local-probe and 'macroscopic’ measurements will provide a comprehensive picture of the nanostructured hybrids at hand. The experimental efforts, backed up by a theoretical study of fundamental properties of HTS as reflected in our measurements, will be carried out by groups in Germany (Konstanz University) and Israel (The Technion, Bar-Ilan University, and the Hebrew University). These four groups have complementary, wellestablished expertise in the necessary material preparation, characterization and research techniques. We expect that the well-balanced combination of overlapping and complementary fields of expertise and interest of our groups will promote a synergetic collaboration and yield new insight into the physics of HTS and their hybrids with ferromagnets.