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 15.7: Poster

Dienstag, 27. März 2007, 15:00–19:00, Poster A

Physical properties and microstructure of La_0,67Ce_0,33MnO₃ thin films — •Christian Stingl, Vasily Moshnyaga, Yuansu Luo, Bernd Damaschke, and Konrad Samwer — I. Physikalisches Institut der Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen

In the perowskite manganites A_1−xB_xMnO₃, the replacement of a trivalent A-ion by a divalent B-ion, which is the case in the majority of the compounds, is usually referred to as hole-doping. Cerium has been suggested as a tetravalent substituent to achieve electron-doping in PLD thin films of La_0,67Ce_0,33MnO₃ (LCeMO) [1]. However, LCeMO seems to be structurally unstable and the single-phase nature of the PLD films has been questioned [2].

We have therefore tried two other deposition techniques and prepared thin La_0,67Ce_0,33MnO₃ films by magnetron sputtering and MAD (metal-organic aerosol deposition) and investigated their microstructure with TEM. In both cases, a chemical phase separation is observed: The sputtered samples are insulating over a wide temperature range but show an interesting form of self-organized growth, with ≈10 nm thick cylindrical columns of a Ce-rich phase embedded in a manganite matrix. The MAD samples exhibit ferromagnetic metallic behavior for T<T_MI≈260 K due to self-doping by La vacancies.

[1] C. Mitra et al., J. Appl. Phys. 89 (2000), 524.

[2] T. Yanagida et al., Phys. Rev. B 70 (2004), 184437.