Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 13: Poster Ia: Electron Theory (1); Magnetic Imaging (2,3); Thin Films (4-25); MSMA (26-33); Magn. Semiconductors (34-42); Magn. Half Metals and Oxides (43-60)

MA 13.58: Poster

Tuesday, March 24, 2009, 10:15–13:00, P1A

Atomic-scale images of the paramagnetic insulating state in a Pr_0.68Pb_0.32MnO₃ single crystal — •Sahana Roessler¹, Steffen Wirth¹, Frank Steglich¹, B Padmanabhan², Suja Elizabeth², and H. L. Bhat² — ¹Max Planck Institute for Chemical Physics of Solids, Nöthnizer Straße 40, 01187, Dresden, Germany — ²Department of Physics, Indian Institute of Science, Bangalore 560012, India

Scanning tunneling microscopy and spectroscopy (STM/S) have been performed on a colossal magnetoresistive manganite Pr_0.68Pb_0.32MnO₃ (PPMO) single crystal. In this compound, the metal-insulator transition occurs at temperature T_MI = 255 K[1]. STS revealed inhomogeneous maps of the zero-bias conductance with small patches of metallic clusters on a length scale of 2-3 nm only within a narrow temperature range close to but below the metal-insulator transition [2]. Here we present atomic-scale images taken at ambient temperature in the paramagnetic insulating state. The room-temperature image clearly depict the square lattice expected for the (010) suface of PPMO in a simple cubic notation. The corresponding lattice constant a₀ =3.75 ±0.6 Å is in agreement with the value determined by powder x-ray diffraction. We will also present STS results on an atomically resolved surface of PPMO.

[1] B. Padmanabhan et al. J. Magn. Magn. Mat. 307 288 (2006). [2] S. Rößler et al. Euro. Phys. Lett. 83 17009 (2008).