Superconductor; Single crystals; High-pressure; Iron-arsenide-superconductors
Karpinski J (2012), High pressure in the synthesis and crystal growth of superconductors and III-N semiconductors, in PHILOSOPHICAL MAGAZINE
, 92(19-21), 2662-2685.
Tortello M, Daghero D, Ummarino GA, Stepanov VA, Zhigadlo ND, Karpinski J, Jiang J, Gonnelli RS (2012), Point-Contact Andreev-Reflection Spectroscopy in Fe-Based Superconductors: Multigap Superconductivity and Strong Electron-Boson Interaction, in JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
, 25(5), 1297-1301.
Gonnelli RS, Tortello M, Daghero D, Kremer RK, Bukowski Z, Zhigadlo ND, Karpinski J (2012), Point-contact spectroscopy in Co-doped CaFe2As2: nodal superconductivity and topological Fermi surface transition, in SUPERCONDUCTOR SCIENCE & TECHNOLOGY
, 25(6), 65007-65017.
Razzoli E, Kobayashi M, Strocov VN, Delley B, Bukowski Z, Karpinski J, Plumb NC, Radovic M, Chang J, Schmitt T, Patthey L, Mesot J, Shi M (2012), Bulk Electronic Structure of Superconducting LaRu2P2 Single Crystals Measured by Soft-X-Ray Angle-Resolved Photoemission Spectroscopy, in PHYSICAL REVIEW LETTERS
, 108(25), 257005-257009.
Blachowski A, Ruebenbauer K, Zukrowski J, Bukowski Z, Matusiak M, Karpinski J (2012), Interplay Between Spin Density Wave and Superconductivity in '122' Iron Pnictides: Fe-57 Mossbauer Study, in ACTA PHYSICA POLONICA A
, 121(4), 726-729.
Das P, Rastovski C, O'Brien TR, Schlesinger KJ, Dewhurst CD, DeBeer-Schmitt L, Zhigadlo ND, Karpinski J, Eskildsen MR (2012), Observation of Well-Ordered Metastable Vortex Lattice Phases in Superconducting MgB2 Using Small-Angle Neutron Scattering, in PHYSICAL REVIEW LETTERS
, 108(16), 167001-167005.
Loudon JC, Bowell CJ, Zhigadlo ND, Karpinski J, Midgley PA (2012), Imaging flux vortices in MgB2 using transmission electron microscopy, in PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
, 474, 18-20.
Gutierrez J, Raes B, Silhanek AV, Li LJ, Zhigadlo ND, Karpinski J, Tempere J, Moshchalkov VV (2012), Scanning Hall probe microscopy of unconventional vortex patterns in the two-gap MgB2 superconductor, in PHYSICAL REVIEW B
, 85(9), 094511-094521.
Moll PJW, Kanter J, McDonald RD, Balakirev F, Blaha P, Schwarz K, Bukowski Z, Zhigadlo ND, Katrych S, Mattenberger K, Karpinski J, Batlogg B (2011), Quantum oscillations of the superconductor LaRu2P2: Comparable mass enhancement lambda approximate to 1 in Ru and Fe phosphides, in PHYSICAL REVIEW B
, 84(22), 224507-224517.
Zhang J, Belousov A, Karpinski J, Batlogg B, Wicks G, Sobolewski R (2011), Time-resolved femtosecond optical characterization of multi-photon absorption in high-pressure-grown Al0.86Ga0.14N single crystals, in JOURNAL OF APPLIED PHYSICS
, 110(11), 113112-113117.
Ciszek M, Rogacki K, Karpinski J (2011), Effect of carbon substitution on low magnetic field AC losses in MgB2 single crystals, in PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
, 471(21-22), 794-797.
Blachowski A, Ruebenbauer K, Zukrowski J, Bukowski Z, Rogacki K, Moll PJW, Karpinski J (2011), Interplay between magnetism and superconductivity in EuFe2-xCoxAs2 studied by Fe-57 and Eu-151 Mossbauer spectroscopy, in PHYSICAL REVIEW B
, 84(17), 174503-174513.
Zhigadlo ND, Katrych S, Bendele M, Moll PJW, Tortello M, Weyeneth S, Pomjakushin VY, Kanter J, Puzniak R, Bukowski Z, Keller H, Gonnelli RS, Khasanov R, Karpinski J, Batlogg B (2011), Interplay of composition, structure, magnetism, and superconductivity in SmFeAs1-xPxO1-y, in PHYSICAL REVIEW B
, 84(13), 134526-134536.
Guguchia Z, Bosma S, Weyeneth S, Shengelaya A, Puzniak R, Bukowski Z, Karpinski J, Keller H (2011), Anisotropic magnetic order of the Eu sublattice in single crystals of EuFe2-xCoxAs2 (x=0,0.2) studied by means of magnetization and magnetic torque, in PHYSICAL REVIEW B
, 84(14), 144506-144516.
Guguchia Z, Shermadini Z, Amato A, Maisuradze A, Shengelaya A, Bukowski Z, Luetkens H, Khasanov R, Karpinski J, Keller H (2011), Muon-spin rotation measurements of the magnetic penetration depth in the iron-based superconductor Ba1-xRbxFe2As2, in PHYSICAL REVIEW B
, 84(9), 094513-094523.
Khasanov R, Sanna S, Prando G, Shermadini Z, Bendele M, Amato A, Carretta P, De Renzi R, Karpinski J, Katrych S, Luetkens H, Zhigadlo ND (2011), Tuning of competing magnetic and superconducting phase volumes in LaFeAsO0.945F0.055 by hydrostatic pressure, in PHYSICAL REVIEW B
, 84(10), 100501-100511.
Since the first report on superconductivity at 26 K in F-doped LaFeAsO at the end of February 2008, the superconducting transition temperature has been quickly raised to about 55 K and many new superconductors have been found. Superconductors with higher critical temperature might be expected. Superconductors and related compounds of high current interest derive their electronic properties from a rather complex interplay of electronic states that are associated with the various constituents that make up the unit cell. Both chemical and structural subtleties can play a decisive role, and require a thorough and systematic study. Our aims are synthesis and investigations of structural properties of single crystals and polycrystalline samples of strongly anisotropic compounds such as high temperature or novel superconductors, FeAs based and related compounds. The study of the influence of chemical substitutions on the superconducting properties is also the aim of the project. By substituting a small amount of foreign elements in the structure one can vary the electron count, create defects or modify the electronic structure leading to an increase of the upper critical field Hc2 or critical temperature and variation of other superconducting parameters. Our aims are to grow single crystals and to synthesize polycrystalline samples of pnictides superconductors for investigations of structural and anisotropic physical properties. We will also perform systematic search for new superconductors. In addition to our own investigations of the material, we also collaborate with many laboratories, both in Switzerland and around the world. As we are one of few labs growing such crystals, there is a worldwide interest for collaboration with our group. In the last years, the interest in column III-nitride materials has become of technical significance due to their optical and electrical properties. In the field of energy efficient lighting, and related applications, there is currently a great need of solid-state light emitters with wavelength in the blue-ultraviolet range. Many nitride-based devices include heterostructures involving binary or ternary alloys of GaN, AlN and InN. In particular, ternaries such as (Al,Ga)N are a class of key materials, and conductive n-type and p-type (Al,Ga)N alloys with high Al contents are especially important for applications. Using high nitrogen pressure and high temperature solution growth technique we were able to grow for the first time (Al,Ga)N single crystals and thick epitaxialy oriented layers on the AlN substrate. Thick layer, subsequently separated from the substrate, can be used for epitaxial growth of device heterostructures or as a seed for the growth of larger crystals. Growth of crystals and layers and investigations of their physical properties will be the subject of the proposed research project.