From measurements of fluctuation spectroscopy and weak nonlinear transport on the semimetallic ferromagnet EuB6 we find direct evidence for magnetically-driven electronic phase separation consistent with the picture of percolation of magnetic polarons (MP), which form highly conducting magnetically-ordered clusters in a paramagnetic and 'poorly conducting' background. These different parts of the conducting network are probed separately by the noise spectroscopy/nonlinear transport and the conventional linear resistivity. We suggest a comprehensive and 'universal' scenario for the MP percolation, which occurs at a critical magnetization either induced by ferromagnetic order at zero field or externally applied magnetic fields in the paramagentic region.
@article{arxiv.1204.6222,
title = {Magnetically-driven electronic phase separation in the semimetallic ferromagnet EuB$_6$},
author = {P. Das and A. Amyan and J. Brandenburrg and J. Müller and P. Xiong and S. von Molnár and Z. Fisk},
journal= {arXiv preprint arXiv:1204.6222},
year = {2012}
}