Regensburg 2007 – scientific programme

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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 15.131: Poster

Tuesday, March 27, 2007, 15:00–19:00, Poster A

Investigation of high-k materials RScO₃ (R=Sm,Gd,Dy) by XPS and band structure calculations — •M. Raekers¹, S. Bartkowski¹, K. Kuepper², S. Zhou², K. Potzger², A. Postnikov³, R. Uecker⁴, and M. Neumann¹ — ¹Universität Osnabrück, Fachbereich Physik, Osnabrück, Germany — ²FZ Dresden-Rossendorf, Dresden, Germany — ³Université Paul Verlaine, Metz, France — ⁴IKZ, Berlin, Germany

There has been considerable interest in high-k-dielectrics rare earth oxides as replacement for SiO₂ in advanced field-effect transistors (FETs). Promising candidates are the perovskites SmScO₃, GdScO₃ and DyScO₃. A tendency towards antiferromagnetic ordering at low temperatures is observed for the high magnetic moments at rare earth atoms. We analyse the electronic structure of the single crystalline samlpes by means of X-ray photoelectron spectroscopy and first-principles theory. The electronic structure calculations are performed with the augmented plane waves method (WIEN2k code) of the density functional theory, taking into account the spin-orbit interaction and orbital-dependent potential (LDA+U). The calculated positions of the main features in the valence band agree with the XPS data, the underlying chemical bonding can be analysed in detail. Small differences in the electronic structure, resulting in different stability of ferro- and antiferromagnetic configurations, are discussed.