Karin Schmalzl

Competing ferri- and antiferromagnetic phases in geometrically frustrated LuFe2O4.

We present a detailed study of magnetism in LuFe(2)O(4), combining magnetization measurements with neutron and soft x-ray diffraction. The magnetic phase diagram in the vicinity of T(N) involves a metamagnetic transition separating an antiferro- and a ferrimagnetic phase. For both phases the spin structure is refined by neutron diffraction. Observed diffuse magnetic scattering far above T(N) is explained in terms of near degeneracy of the magnetic phases.

Protein-Protein Interaction in Purple Membrane

Maikel C. Rheinstädter, Karin Schmalzl, Kathleen Wood, and Dieter Strauch Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65203, U.S.A. Institut Laue-Langevin, 6 rue Jules Horowitz, B.P. 156, F-38042 Grenoble Cedex 9, France Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany Institut de Biologie Structurale Jean Pierre Ebel CEA-CNRS-UJF, F-38027 Grenoble Cedex 1, France and Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany (Dated: September 28, 2008)

Flop of electric polarization driven by the flop of the Mn spin cycloid in multiferroic TbMnO3.

N. Aliouane, 2 K. Schmalzl, D. Senff, A. Maljuk, K. Prokeš, M. Braden, and D. N. Argyriou ∗ Helmholtz-Zentrum Berlin für Materialen und Energy, Glienicker Str. 100, D-14109 Berlin, Germany Institute For Energy, P.O. Box 40, NO-2027 Kjeller, Norway Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, JCNS at ILL, 38042 Grenoble Cedex 9, France II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany (Dated: February 11, 2009)

Single to Multiquasiparticle Excitations in the Itinerant Helical Magnet CeRhIn5

CeRhIn(5) is an itinerant magnet where the Ce(3+) spins order in a simple helical phase. We investigate the spin excitations and observe sharp spin waves parameterized by a nearest-neighbor exchange, J(RKKY)=0.88±0.05  meV. At higher energies, the spin fluctuations are heavily damped, where single-quasiparticle excitations are replaced by a momentum- and energy-broadened continuum constrained by kinematics of energy and momentum conservation. The delicate energy balance between localized and itinerant characters results in the breakdown of the single-quasiparticle picture in CeRhIn(5).

Magnetic excitations in the metallic single-layer ruthenates Ca2−xSrxRuO4studied by inelastic neutron scattering

By inelastic neutron scattering, we have analyzed the magnetic correlations in the paramagnetic metallic region of the series Ca(2-x)Sr(x)RuO(4), 0.2<=x<=0.62. We find different contributions that correspond to 2D ferromagnetic fluctuations and to fluctuations at incommensurate wave vectors (0.11,0,0), (0.26,0,0) and (0.3,0.3,0). These components constitute the measured response as function of the Sr-concentration x, of the magnetic field and of the temperature. A generic model is applicable to metallic Ca(2-x)Sr(x)RuO(4) close to the Mott transition, in spite of their strongly varying physical properties. The amplitude, characteristic energy and width of the incommensurate components vary only little as function of x, but the ferromagnetic component depends sensitively on concentration, temperature and magnetic field. While ferromagnetic fluctuations are very strong in Ca1.38Sr0.62RuO4 with a low characteristic energy of 0.2 meV at T=1.5 K, they are strongly suppressed in Ca1.8Sr0.2RuO4, but reappear upon the application of a magnetic field and form a magnon mode above the metamagnetic transition. The inelastic neutron scattering results document how the competition between ferromagnetic and incommensurate antiferromagnetic instabilities governs the physics of this system.

Anisotropy of incommensurate magnetic excitations in slightly overdoped

Polarized neutron scattering experiments on the slightly overdoped superconductor Ba

{\mathrm{Ba}}_{0.5}{\mathrm{K}}_{0.5}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}

_{0.5}

probed by polarized inelastic neutron scattering experiments

K

Incommensurate antiferromagnetic order in the manifoldly-frustrated SrTb2O4 with transition temperature up to 4.28 K

_{0.5}

Distinct itinerant spin-density waves and local-moment antiferromagnetism in an intermetallic ErPd2Si2 single crystal.

Fe