Doping fluctuation-driven magneto-electronic phase separation in LaSr_xCoO₃ single crystals

¹  Department of Chemical Engineering and Materials Science, University of Minnesota Minneapolis, MN 55455, USA
²  NIST Center for Neutron Research, National Institute for Standards and Technology Gaithersburg, MD 20899, USA
³  Materials Science Division, Argonne National Laboratory - Argonne, IL 60439, USA

Corresponding author: leighton@umn.edu

Received: 5 June 2009
Accepted: 9 July 2009

Abstract

In recent years it has become clear that complex oxides provide an exceptional platform for the discovery of new physics as well as a considerable challenge to our understanding of correlated electrons. The tendency of these materials to display nanoscale electronic and magnetic inhomogeneity is a good example. Here, we have applied a variety of experimental techniques to investigate this magneto-electronic phase separation in a model system —the doped cobaltite LaSr_xCoO₃. Comparing experimental data over a wide range of doping with statistical simulations, we conclude that the magneto-electronic inhomogeneity is driven solely by inevitable local compositional fluctuations at nanoscopic length scales. The phase separation is thus doping fluctuation-driven rather than electronically driven, meaning that more complex electronic phase separation models are not required to understand the observed phenomena in this material.