Berlin 2008 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 34: Correlated Electrons: Metal-Insulator Transition 2
TT 34.14: Talk
Thursday, February 28, 2008, 17:45–18:00, H 2053
Nanometer-scale phase separation in colossal magnetoresistive manganite — •Sahana Roessler1, Stefan Ernst1, 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
In strongly correlated electron systems an intrinsic instability of the electronic state and competing long-range interactions may result in the formation of nanometer-sized regions of different phases. We have carried out scanning tunneling microscopy/spectroscopy on single crystals of a colossal magnetoresistive manganite Pr0.68Pb0.32MnO3 at different temperatures in order to probe their spatial homogeneity across the metal-insulator transition temperature TM−I. In this compound, the Curie temperature TC is lower than TM−I [1]. Spectroscopic studies 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 the metal-insulator transition. A detailed analysis of conductance histograms based on these maps gave direct evidence for phase separation into insulating and metallic regions in the paramagnetic metallic state, i.e. for TC T TM−I, and homogeneous states otherwise, i.e. for T < TC as well as T > TM−I [2].
[1] B. Padmanabhan et al. J. Magn. Magn. Mat. 307 288 (2006).
[2] S. Rößler et al. IEEE Trans. Magn. 43 3064 (2007).