Fachbereich Physik

AG Küpper


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Publikationen (seit 2003) / Publications (since 2003)

Peer-reviewed

2015

 

(65) T. Schemme, A. Krampf, F. Bertram, T. Kuschel, K. Kuepper, and J. Wollschläger: "Modifying magnetic properties of ultra-thin magnetite films by growth of Fe pre-covered MgO(001)": J. Appl. Phys., accepted (2015)

(64) T. Schemme, O. Kuschel, F. Bertram, K. Kuepper, J. Wollschläger: "Structure and morphology of epitaxially grown Fe3O4/NiO bilayers on MgO(001)": Thin Solid Films 589, 526 (2015).

(63) H. Schäfer, S. Sadaf, L. Walder, K. Kuepper, S. Dinklage, J. Wollschläger, L. Schneider, M. Steinhart, J. Hardege, and D. Daum: "Stainless steel made to rust: a robust water-splitting catalyst with benchmark characteristics": Energy Environ. Sci. 8, 2685 (2015).

(62) H. Schäfer, S. Mohsen Beladi-Mousavi, L. Walder, J. Wollschläger, O. Kuschel, S. Ichilmann, S. Sadaf, M. Steinhart, K. Küpper, and L. Schneider: "Surface Oxidation of Stainless Steel: Oxygen Evolution Electrocatalysts with High Catalytic Activity", ACS Catalysis 5 (4), 2671-2680, DOI: 10.1021/acscatal.5b00221 (2015).

(61) N. Wagner, L. Schneider, M. Michelswirth, K. Küpper and P. Theato: "Installation of Zwitterionic α-Amino Phosphonic Acid Moieties on Surfaces via a Kabachnik-Fields Post-Polymerization Modification", Macromolecular Chemistry and Physics 216, 783-793, DOI: 10.1002/macp.201400591 (2015).

(60) L. Marnitz, K. Rott, S. Niehörster, C. Klewe, D. Meier, S. Fabretti, M. Witziok, A. Krampf, O. Schuckmann, T. Schemme, K. Kuepper, J. Wollschläger, A. Thomas, G. Reiss, and T. Kuschel: "Sign change in the tunnel magnetoresistance of Fe3O4/MgO/Co-Fe-B magnetic tunnel junctions depending on the annealing temperature and the interface treatment": AIP Advances 5, 047103 (2015).

(59) A. Scheurer, J. Korzekwa, T. Nakajima, F. Hampel, A. Buling, C. Derks, M. Neumann, L. Joly, K. Petukhov, K. Gieb, P. Müller, K. Kuepper, and K. Meyer: "Synthesis, Magnetic Properties, and X-ray Spectroscopy of Divalent Cobalt(II) and Nickel(II) Cubanes [MII4(HL2)4(OAc)4]", European Journal of Inorganic Chemistry 2015, 1872-1901, DOI: 10.1002/ejic.201402988 (2015).

(58) T. Schemme, N. Pathé, K. Kuepper, G. Niu, F. Bertram, T. Kuschel, and J. Wollschläger: "Magnetic anisotropy related to strain and stoichiometry of ultrathin iron oxide films on MgO(001)": Mater. Res. Express 2, 016101 (2015).

 

2014

 

(57) A. Helmstedt, N. Dohmeier, N. Müller, A. Gryzia, A. Brechling, U. Heinzmann, V. Hoeke, E. Krickemeyer, T. Glaser, P. Leicht, M. Fonin, T. Tietze, L. Joly, and K. Kuepper: "Probing the Magnetic Moments of [MnIII6CrIII]3+ Single-Molecule Magnets - A Cross Comparison of XMCD and Spin-Resolved Electron Spectroscopy": J. Electr. Spectr. Rel. Phenom. 198, 12 (2014).

(56) C. Klewe, M. Meinert, A. Boehnke, K. Kuepper, E. Arenholz, A. Gupta, J.M. Schmalhorst, T. Kuschel, and G. Reiss: "Physical characteristics and cation distribution of NiFe2O4 thin films with high resistivity prepared by reactive co-sputtering": J. Appl. Phys. 115, 123903 (2014).

(55) U. Heinzmann, A. Helmstedt, N. Dohmeier, N. Müller, A. Gryzia, A. Brechling, V. Hoecke, E. Krickemeyer, T. Glaser, M. Fonin, S. Bouvron, P. Leicht, T. Tietze, E. Goering, and K. Kuepper: "The local magnetic properties of [MnIII6 CrIII]3+ and [FeIII6 CrIII]3+ single-molecule magnets deposited on surfaces studied by spin-polarized photoemission and XMCD with circularly polarized synchrotron radiation": J. Phys.: Conf. Ser. 488, 132001 (2014).

(54) V. R. Galakhov, S. N. Shamin, V. V. Mesilov, N. A. Ovechkina, M. A. Uimin, A. Ye. Yermakov, L. Schneider, K. Balinski, and B. V. Senkovskiy: "X-ray Absorption and Photoelectron Characterization of Carbon Shell Extracted from Ni@C Nanoparticles", The Journal of Physical Chemistry C 118 (51), 30216-30220, DOI: 10.1021/jp509408w (2014).

(53) A. Gryzia, T. Volkmann, A. Brechling, V. Hoeke, L. Schneider, K. Kuepper, T. Glaser, and U. Heinzmann: "Crystallographic order and decomposition of [MnIII 6CrIII]3+ single-molecule magnets deposited in submonolayers and monolayers on HOPG studied by means of molecular resolved atomic force microscopy (AFM) and Kelvin probe force microscopy in UHV", Nanoscale Research Letters 9, 60 (2014).

(52) K. Kuepper, M. Neumann, A.J.M. Al-Karawi, A. Ghosh, S. Walleck, T. Glaser, P. Gouzerh, and A. Müller: "Immediate Formation/Precipitation of Icosahedrally Structured Iron-Molybdenum Mixed Oxides from Solutions Upon Mixing Simple Iron(III) and Molybdate Salts", Journal of Cluster Science 25, 301-311 (2014).

 

2013

 

(51) T. Grünzel, YJ Lee, K. Kuepper, and J. Bachmann: "Preparation of electrochemically active silicon nanotubes in highly ordered arrays", Beilstein Journal of Nanotechnology 4, 655-664, DOI: 10.3762/bjnano.4.73. (2013).

(50) D. Bruns, S.R. Lindemann, K. Kuepper, T. Schemme, and J. Wollschläger: "Fe3O4 films on Ag(001)-Generation of high-quality epitaxial ferrimagnetic metal oxide films": Appl. Phys. Lett. 103, 052401 (2013).

(49) K. Kuepper, C. Derks, C. Taubitz, M. Prinz, L. Joly, J.P. Kappler, A.V. Postnikov, W.L. Yang, T.V. Kuznetsova, U. Wiedwald, P. Ziemann, and M. Neumann: "Electronic structure and soft X-ray-induced photoreduction studies of iron-based magnetic polyoxometalates of type {(M)M5}12FeIII30 (M=MoVI,WVI), Dalton Transactions 42, 7924, DOI: 10.1039/C3DT32759K (2013).

 

2012

 

(48) U. Wiedwald, F. Haering, S. Nau, C. Schulze, H. Schletter, D. Makarov, A. Plettl, K. Kuepper, M. Albrecht, J. Boneberg, and P. Ziemann: "Tuning the properties of magnetic thin films by interaction with periodic nanostructures", Beilstein Journal of Nanotechnology 3, 831 (2012).

(47) A.V. Postnikov, C. Derks, K. Kuepper, M. Raekers, and M. Neumann: "Electronic structure of rare-earth scandates from X-ray spectroscopy and firstprinciples calculations", Ferroelectrics 438, 45 (2012).

(46) C. Derks, K. Kuepper, M. Raekers, A.V. Postnikov, R. Uecker, W.L. Yang, and M. Neumann: "Band-gap variation in RScO3 (R=Pr, Nd, Sm, Eu, Gd, Tb, and Dy): X-ray absorption and O K-edge x-ray emission spectroscopis", Phys. Rev. B 86, 155124 (2012).

(45) K. Kuepper, M. Raekers, C. Taubitz, M. Uhlarz, C. Piamonteze, F.M.F: de Groot, E. Arenholz, V.R. Galakhov, Ya.M. Mukovskii, and M. Neumann: "The x-ray magnetic circular dichroism spin sum rule for 3d4 systems: Mn3+ ions in colossal magnetoresistance manganites", J. Phys.: Condens. Matter 24, 435602 (2012).

(44) G. Abrasonis, S. Wintz, M.O. Liedke, F.A: Akgul, M. Krause, K. Kuepper, D. Banerjee, Z. Liu, and S. Gemming: "Environment Controlled Dewetting of Rh-Pd Bilayers: A Route for Core-Shell Nanostructure Synthesis":, J. Phys. Chem. C 116, 14401 (2012).

 

2011

 

(43) K. Kuepper, D.M. Benoit, U. Wiedwald, F. Mögele, A. Meyering, M. Neumann, J.P. Kappler, L. Joly, S. Weidle, B. Rieger, and P. Ziemann: "Precise chemical, electronic and magnetic structure of binuclear complexes studied by means of x-ray spectroscopies and theoretical methods", J. Phys. Chem. C 115, 25030 (2011).

(42) K. Kuepper, C. Taubitz, D. Taubitz, U. Wiedwald, A. Scheurer, S. Sperner, R.W. Saalfrank, J.P. Kappler, L. Joly, Paul Ziemann: "Magnetic Ground State and Systematic X-ray Photoreduction Studies of an Ironbased Star-Shaped Complex", J. Phys. Chem. Letters 2, 1491 (2011).

 

2010

 

(41) C. Taubitz, Z. Hu, N. Hollmann, Y.-Y. Chin, K. Kuepper, V. Tsurkan, H.-J. Lin, C.T. Chen, L.-H. Tjeng, and M. Neumann": "Fe valence state at the surface of the Fe0.5Cu0.5Cr2S4 spinel", phys. Stat. solidi RRL 4, 338 (2010).

(40) M.Y. Ge, K.Y. Han, U. Wiedwald, X.B. Xu, C. Wang, K. Kuepper, P. Ziemann and J.Z. Jiang: "Monodispersed NiO nanoflowers with anomalous magnetic behavior", Nanotechnology 21, 425702 (2010).

(39) V.R. Galakhov, E. Z. Kurmaev, K. Kuepper, M. Neumann, J.R. McLeod, A. Moewes, I.A. Leonidov, and V.L. Kozhevnikov: "Valence band structure and x-ray spectra of oxygen deficient ferrites SrFeOx", J. Phys. Chem. C 114, 5154 (2010).

(38) M. Prinz, K. Kuepper, C. Taubitz, M. Raekers, B. Biswas, T. Weyhermüller, M. Uhlarz, J. Wosnitza, J. Schnack, A.V. Postnikov, C. Schröder, S.J. George, M. Neumann, and P. Chaudhuri: "A star-shaped heteronuclear CrIIIMnII3 species and its electronic and magnetic structure: Spin frustration studied by XMCD, high field magnetic measurements and theoretical simulations", Inorg. Chem. 49, 2093 (2010).

 

2009

 

(37) K. Kuepper, M. Raekers, C. Taubitz, C. Derks, S.J. Blundell, F.M.F. de Groot, A.V. Postnikov, and M. Neumann: "Charge order, enhanced orbital moment, and absence of frustration in layered LuFe2O4", Phys. Rev. B 80, 220409(R) (2009).

(36) K. Kuepper, S. Wintz, J. Raabe, Ch. Akhmadaliev, L. Bischoff, C. Quitmann, and J. Fassbender: "The influence of central an non centric holes on the magnetization dynamics of Landau structures", J. Phys.: Condens. Matter 21, 436003 (2009).

(35) S. Zhou, K. Potzger, Q. Xu, K. Kuepper, G. Talut, D. Markó, A. Mücklich, M. Helm, J. Fassbender, E. Arenholz, and H. Schmidt: "Spinel ferrite nanocrystals embedded inside ZnO: magnetic, electronic and magnetotransport properties": Phys. Rev. B 80, 094409 (2009).

(34) C. Taubitz, K. Kuepper, M. Raekers, V.R. Galakhov, V. Felea, V. Tsurkan, and M. Neumann: "Reinvestigation of the Fe valences in (FeCu)Cr2S4 spinels", phys. stat. sol. b 246, 1470 (2009).

(33) S. Zhou, K. Potzger, D. Brüger, K. Kuepper, M. Helm, J. Fassbender, and H. Schmidt: "Inverse spinel ZnFe2O4 nanoparticles synthesized by ion implantation and postannealing: An investigation using x-ray spectroscopy and magnetic transport", Nucl. Instr. and Meth. B 267, 1620 (2009).

(32) M. Raekers, K. Kuepper, S. Bartkowski, A.V. Postnikov, M. Prinz, K. Potzger, S. Zhou, A. Arulraj, N. Stüßer, R. Uecker, W.L. Wang, and M. Neumann: "Electronic and magnetic structure of RScO3 (R = Sm,Gd,Dy) from x-ray spectroscopies and first-principles calculations", Phys. Rev. B 79, 125114 (2009).

(31) M. Neumann and K. Kuepper: "X-ray spectroscopic techniques are powerful tools for electronic structure investigations of transition metal oxides", Surface Science 603, 1613 (2009).

(30) M. Prinz, M. Raekers, M. Neumann, K. Kuepper, S. Khanra, T. Weyhermüller and P. Chaudhuri: "Synthesis, structure, and valency verification of a Mn(III)6O2-cluster", Z. Phys. Chem. 223, 145 (2009).

 

2008

 

(29) V.R. Galakhov, M.C. Falub, K. Kuepper, and M. Neumann: "X-ray spectroscopy of lanthanum manganites: Nature of doping holes, correlation effects, and orbital ordering", J. of Structural Chemistry 49, 54 (2008).

(28) G. Abrasonis, M. Berndt, M. Krause, K. Kuepper, F. Munnik, A. Kolitsch and W. Möller: "Soft X-ray Absorption and Emission Spectroscopic Investigation of Carbon and Carbon:Transition Metal Composite Films", J. Phys. Chem. C 112, 17161 (2008).

(27) K. Kuepper, M. Raekers, C. Taubitz, H. Hesse, M. Neumann, A. T. Young, C. Piamonzeze, F. Bondino and K. C. Prince: "Fe valence state of Sr2FeMoO6 probed by x-ray absorption spectroscopy: the sample age matters", J. Appl. Phys. 104, 036103 (2008).

(26) K. Potzger, K. Kuepper, Q. Xu, S. Zhou, H. Schmidt, M. Helm and J. Fassbender: "High cluster formation tendency in Co implanted ZnO", J. Appl. Phys. 104, 023510 (2008).

(25) G. Abrasonis, A. C. Scheinost, S. Zhou, R. Torres, R. Gago, I. Jimenez, K. Kuepper, K. Potzger, M. Krause, A. Kolitsch, W. Moeller, S. Bartkowski, M. Neumann and R. R: Gareev: "X-ray Spectroscopic and Magnetic Investigation of C:Ni Nanocomposite Films Grown by Ion Beam Cosputtering", J. Phys. Chem. C 112, 12628 (2008).

(24) S. Zhou, K. Potzger, G. Talut, H. Reuther, K. Kuepper, J. Grenzer, Q. Xu, A. Muecklich, M. Helm, J. Fassbender and E. Arenholz: "Ferromagnetism and suppression of metallic clusters in Fe implanted ZnO: a phenomenon related to defects?", Journal of Physics D: Applied Physics 41, 105011 (2008).

(23) S. Khanra, K. Kuepper, T. Weyermüller, M. Prinz, M. Raekers, S. Voget, A. V. Postnikov, F. M. F. De Groot, S. J. George, M. Coldea, M. Neumann and P. Chaudhuri: "Star-Shaped molecule of Mn(II)4O6 Core with an St=10 High-Spin State: A Theoretical and Experimental Study with XPS, XMCD, and Other Magnetic Methods", Inorg. Chem. 47, 4605 (2008).

(22) S. Zhou, K. Potzger, K. Kuepper, J. Grenzer, M. Helm, J. Fassbender, E. Arenholz and J. D. Denlinger: "Ni implanted ZnO single crystals: Correlation between nanoparticle formation and defect structure": J. Appl. Phys. 103, 043901 (2008).

 

2007

 

(21) K. Kuepper, J. Raabe, M. Buess, C. Quitmann, and J. Fassbender: "Dynamic vortex - antivortex interaction in a single cross-tie wall", Phys. Rev. Lett. 99, 167202 (2007), and Virt. J. Nanoscale Sci. and Technol., October 2007.

(20) K. Potzger, S. Zhou, H. Reuther, G. Talut, K. Kuepper, M. Helm, J. Fassbender, and J. D. Denlinger: "Strong suppression of secondary phase formation in Fe implanted ZnO single crystals", Appl. Phys. Lett. 91, 062107 (2007).

(19) S. Zhou, K. Potzger, H. Reuther, K. Kuepper, W. Skorupa, M. Helm, and J. Fassbender : "Absence of ferromagnetism in V-implanted ZnO single crystals", J. Appl. Phys. 101, 09H109 (2007).

(18) K. Kuepper, L. Bischoff, J. Fassbender, H. Stoll, K. W. Chou, B. Van Waeyenberge, A. Puzic, K. Fauth, D. Dolgos, G. Schütz, T. Tyliszczak, I. Neudecker, G. Woltersdorf, and C. H. Back: "Vortex dynamics in permalloy disks with artificial point defects: Suppression of the gyrotropic mode", Appl. Phys. Lett. 90, 62506 (2007).

 

2006

 

(17) T.O. Mentes, F. Bondino, E. Magnano, M. Zangrando, K. Kuepper, V.R. Galakhov, Ya.M. Mukovskii, M. Neumann, and F. Parmigiani: "Excitation Dynamics in La0.875Sr0.125MnO3 measured by Resonant Auger Electron and Resonant X-ray Emission Spectroscopies": Phys. Rev. B 74, 205409 (2006).

(16) K. Kuepper, R. Klingeler, P. Reutler, B. Büchner, and M. Neumann: "Exited state and ground state properties of LaSrMnO4: A combined x-ray spectroscopic study": Phys. Rev. B 74, 115103 (2006).

(15) V.R. Galakhov, N.A. Ovechkina, A.S. Shkvarin, S.N. Shamin, E.Z. Kurmaev, K. Kuepper, A.F. Takács, M. Raekers, S. Robin, M. Neumann, G.N. Gavrilă, A.S. Semenova, D.G. Kellermann, T. Käämbre, and J. Nordgren: "Valence band spectra and electronic structure of defective oxides LixCoO2": Phys. Rev. B 74, 045120 (2006).

(14) M. Raekers, K. Kuepper, H. Hesse, I. Balasz, E. Burzo, and M. Neumann: "Investigation of chemical and grain boundary effects in highly ordered Sr2FeMoO6: XPS and Mössbauer studies": Journal of Optoelectronics and Advanced Materials 8, 455 (2006).

(13) K. Kuepper, R. Klingeler, P. Reutler, B. Büchner, and M. Neumann: "Electronic structure of LaSrMnO4: XPS and XES studies": J. Appl. Phys. 99, 08Q308 (2006).

(12) M. Prinz, A. Takács, J. Schnack, I. Balasz, E. Burzo, U. Kortz, K. Kuepper, and M. Neumann: "Magnetic and electronic properties of the iron-containing polyoxotungstate [Fe4(H2O)10(β-SbW9O33)2]6-": J. Appl. Phys. 99, 08J505 (2006).

(11) A. F. Takács, M. Neumann, A.V. Postnikov, K. Kuepper, A. Scheurer, S. Sperner, R.W. Saalfrank, and K.C. Prince: "Electronic structure study by means of X-ray spectroscopy and theoretical calculations of the "ferric star" single molecule magnet": J. Chem. Phys. 124, 044503 (2006).

 

2005

 

(10) K. Kuepper, F. Bondino, K.C. Prince, M. Zangrando, M. Zacchigna, A.F. Takács, T. Crainic, M. Matteucci, F. Parmigiani, V R. Galakhov, Ya.M. Mukovskii, A. Winiarski, and M. Neumann: "Direct Investigation Colossal Magnetoresistance Manganite by Means of X-ray Linear Dichroism at the Mn L Edge": J. Phys. Chem. B Letters 109, 15667 (2005).

(9) K. Kuepper, M. Kadiroglu, A. V. Postnikov, K. C. Prince, M. Matteucci, V.R. Galakhov, H. Hesse, G. Borstel, and M. Neumann: "Electronic Structure of highly ordered Sr2FeMoO6": J. Phys.: Condens. Matter 17, 4309 (2005).

(8) A.Y. Yermakov, M.A. Uimin, V.R. Galakhov, A A. Mysik, O.V. Koryakova, V.G. Kharchuk, V.A. Vykhodetz, V.S. Gaviko, K. Kuepper, S. Robin, and M. Neumann:"Structure and Surface States of Cu-O Based Nanocrystalline Powders": Journal of Metastable and Nanocrystalline Materials 24-25, 43 (2005).

(7) K. Kuepper, M.C. Falub, K.C. Prince, V R. Galakhov, I.O. Troyanchuk, S.G. Chiuzbăian, M. Matteucci, D. Wett, R. Szargan, N.A. Ovechkina, Ya.M. Mukovskii, and M. Neumann: "Electronic structure of A- and B- site doped Lanthanum manganites: A combined x-ray spectroscopic study": J. Phys. Chem. B 109, 9354 (2005).

(6) K.C. Prince, F. Bondino, M. Zangrando, M. Zacchigna, F. Parmigiani, K. Kuepper, and M. Neumann: "Dichroic O 1s photoabsorption and resonant x-ray scattering in haematite (Fe2O3)": Journ. of Electr. Spectr. and Rel. Phenom.144-147, 719 (2005.

(5) K.C. Prince, M. Matteucci, K. Kuepper, S. G. Chiuzbăian, S. Bartkowski, and M. Neumann: "A core level spectroscopic study of iron monoxide (FeO) and pyrite (FeS2)": Phys. Rev. B 71, 085102 (2005).

 

2004

 

(4) K. Kuepper, I. Balasz, H. Hesse, A. Winiarski, K C. Prince, M. Matteucci, D. Wett, R. Szargan, E. Burzo, and M. Neumann: "Electronic and magnetic properties of highly ordered Sr2FeMoO6": phys. stat. sol. (a) 201 (15), 3252 (2004).

(3) K. Kuepper, A. V. Postnikov, A. Moewes, B. Schneider, M. Matteucci, H. Hesse, and M. Neumann: "The electronic structure of KTaO3: a combined x-ray spectroscopic investigation": J. Phys.: Condens. Matter 16, 8213 (2004).

 (2) K. C. Prince, K. Kuepper, M. Neumann, D. Cocco, F. Bondino, M. Zangrando, M. Zacchigna, M. Matteucci, and F. Parmigiani: "Resonant Raman x-ray scattering at the S 2p edge of iron pyrite": J. Phys.: Condens. Matter 16, 7397 (2004).

 

2003

 

(1) K. Kuepper, B. Schneider, V. Caciuc, M. Neumann, A. V. Postnikov, A. Ruediger, A.A. Grabar, and Yu. M. Vysochanskii: "Electronic structure of Sn2P2S6": Phys. Rev. B 67, 11501 (2003).

 

Book chapters

 

(1) "Dynamics of Mesoscopic Magnetic Objects": C. Quitmann, J. Raabe, A. Puzic, K. Kuepper, and S. Wintz: E. Beaurepaire et al. (eds.), Magnetism and Synchrotron Radiation, Proceedings in Physics 133, Springer-Verlag Berlin Heidelberg 2010.