Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)
MA 15.121: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Crystal structure and magnetic fluctuations in La1−xA xCoO3 (A = Ca, Sr, Ba) — •Thomas Finger1, Marco Reuther1, Daniel Senff1, Matthias Cwik1, Thomas Lorenz1, Klaudia Hradil2, Anatoliy Senychyn3, and Markus Braden1 — 1II. Physikalisches Institut, Universität zu Köln — 2Institut für Physikalische Chemie, Georg-August Universität Göttingen — 3FB Material- und Geowissenschaften, Technische Universität Darmstadt
The phase diagram of perovskite cobaltites is closely related to those of the CMR-manganites as they both show ferromagnetism and metallic behaviour at intermediate doping. We have studied the crystal structure of the series with Ca and Ba doping by combining different neutron and x-ray diffraction techniques and will discuss the corresponding phase diagrams. Furthermore magnetic excitations were studied by inelastic neutron scattering on a thermal triple-axis spectrometer for La0.75Sr0.25CoO3 which exhibits ferromagnetic order below TC = 220 K.The magnon excitations could be followed up to energies of 13 THz yielding an isotropic dispersion. We find a spin-wave stiffness constant of D=400±35meV·Å2.