Colossal magnetotransport phenomena due to phase competition in Pr 1-x(CaySr1-y) xMnO3 single crystals

J. Wu, H. Zheng, J. F. Mitchell, C. Leighton

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

We present a magnetotransport investigation of single crystal Pr 0.65(Ca0.75Sr0.25)0.35MnO 3, a manganite system specifically tailored to result in a close competition between ferromagnetic metallic and charge ordered antiferromagnetic insulating phases. Below 165 K these phases coexist spatially, with application of a magnetic field favoring the ferromagnetic metallic phase, leading to a magnetoresistance ratio of>1010 in a 2 T magnetic field. Isothermal resistivity vs. field measurements reveal some previously unobserved features accompanying the insulator to metal transition. In addition to unexpected fine structure that occurs as the ferromagnetic metallic phase grows to engulf the entire sample, we observe an intriguing "overshoot" phenomenon in both temperature and field-driven insulator-metal transitions. The resistivity is found to reach a sharp minimum (lower even than the pure ferromagnetic metallic phase) close to the point where the metallic phase percolates. These features are explored in detail and we discuss possible explanations of the effects in terms of pinning of the spatial boundary between the magnetic phases, and the unusual transport effects that could occur when the current flows through a barely percolated path.

Original languageEnglish (US)
Pages (from-to)146-154
Number of pages9
JournalJournal of Magnetism and Magnetic Materials
Volume288
DOIs
StatePublished - Mar 1 2005

Keywords

  • Colossal magnetoresistance
  • Manganites
  • Metal-insulator transition
  • Phase separation

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