Percolative conductivity and critical exponents in mixed-valent manganites
Abstract
Recent experiments have shown that some colossal magnetoresistance (CMR) materials exhibit a percolation transition. The conductivity exponent varies substantially with or without an external magnetic field. This finding prompted us to carry out theoretical studies of percolation transition in CMR systems. We find that the percolation transition coincides with the magnetic transition and this causes a large effect of a magnetic field on the percolation transition. Using real-space-renormalization method and numerical calculations for two-dimensional (2D) and three-dimensional (3D) models, we obtain the conductivity exponent to be 5.3 (3D) and 3.3 (2D) without a magnetic field, and 1.7 (3D) and 1.4 (2D) with a magnetic field.
Keywords
Cite
@article{arxiv.cond-mat/0102083,
title = {Percolative conductivity and critical exponents in mixed-valent manganites},
author = {Ye Xiong and Shun-Qing Shen and X. C. Xie},
journal= {arXiv preprint arXiv:cond-mat/0102083},
year = {2009}
}
Comments
4 pages, 4 figures. To appear in Rapid Communications of Phys. Rev. B