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Phys. Rev. Lett. 93, 037203 (2004) [4 pages]

Imaging of Percolative Conduction Paths and Their Breakdown in Phase-Separated (La1-yPry)0.7Ca0.3MnO3 with y=0.7

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M. Tokunaga*, Y. Tokunaga, and T. Tamegai
Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Received 10 February 2004; published 15 July 2004

Local magnetization and current distribution in (La1-yPry)0.7Ca0.3MnO3 (y=0.7) crystals are studied by a magneto-optical (MO) imaging technique. MO images below 120 K visualize inhomogeneous magnetization and conduction paths that manifest the percolative conduction originated from the mesoscopic phase separation into ferromagnetic metals and antiferromagnetic insulators. Application of large amounts of current switches the current distribution from inhomogeneous to homogeneous concomitantly with a steep increase in resistivity. These phenomena are discussed in view of current induced collapse of the phase separation through a local heating.

© 2004 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.93.037203
DOI:
10.1103/PhysRevLett.93.037203
PACS:
75.47.Lx, 64.60.Ak, 64.75.+g, 71.30.+h

*Electronic address: mtokunaga@ap.t.u-tokyo.ac.jp