Advertisement

Journal of Superconductivity

, Volume 18, Issue 5–6, pp 659–662 | Cite as

Evidence of Phase Separation in the P-T Phase Diagram of the La0.75Ca0.25MnO3 Manganite by Infrared Measurements

  • P. Dore
  • A. Sacchetti
  • P. Postorino
  • A. Congeduti
  • F. A. Gorelli
  • L. Ulivi
Article
  • 32 Downloads

Abstract

Recent infrared absorption measurements performed at different pressures and temperatures on the La0.75Ca0.25MnO3 manganite provided an estimate of the insulator-to-metal transition temperature T IM(P), i.e., the P-T phase diagram of a pseudocubic manganite. Here we consider in detail the P- and T-dependence of the absorption spectral weights n *. The n *(T,P) behavior gives evidence of phase-separation between conducting and insulating domains in the P-T phase diagram, and allows to establish the occurrence of a characteristic temperature T * ≅ 0.6 T IM. For T > T *, when insulating domains decrease on decreasing temperature or on increasing pressure, it is possible to distinguish a metallic region (connected metallic domains) for T * < T < T IM, and an insulating region (disconnected metallic domains) for T > T IM. Below T *, no reduction of the insulating domains, that may still exist, occurs.

KEY WORDS:

manganites infrared spectroscopy phase separation 

References

  1. 1.
    J. M. D. Coey et al., Adv. Phys. 48, 167 (1999).ADSCrossRefGoogle Scholar
  2. 2.
    Colossal Magneto-resistance Oxides, Y. Tokura, ed., Monographs in Condensed Matter Science, Gordon and Breach, Reading, U.K. (2000).Google Scholar
  3. 3.
    E. Dagotto et al., Phys. Rep. 344, 1 (2001); E. Dagotto, Nanoscale Phase Separation and Colossal Magnetoresistance (Springer-Verlag, Berlin, 2002). Google Scholar
  4. 4.
    A. J. Millis, Nature 392, 147 (1998).ADSCrossRefGoogle Scholar
  5. 5.
    Y. Murakami et al., Nature 423, 965 (2003); B. B. Van Aken et al., Phys. Rev. Lett. 90, 066403 (2003).Google Scholar
  6. 6.
    M. Uehara et al., Nature 399, 560 (1999); J. Burgy et al., Phys. Rev. Lett. 87, 277202 (2001).Google Scholar
  7. 7.
    V. Cataudella et al., Phys. Rev. B 63, 052406 (2001).ADSCrossRefGoogle Scholar
  8. 8.
    A. Weisse et al., Phys. Rev. B 68, 024402 (2003); M. Garcia-Hernandez et al., Phys. Rev. B 68, 094411 (2003)Google Scholar
  9. 9.
    P. Postorino et al., Phys. Rev. Lett. 91, 175501 (2003).ADSCrossRefGoogle Scholar
  10. 10.
    A. Congeduti et al., Phys. Rev. B 63, 184410 (2001).ADSCrossRefGoogle Scholar
  11. 11.
    H. Y. Hwang et al., Phys. Rev. B 52, 15046 (1995); V. Laukhin et al., Phys. Rev. B 56, R10009 (1997).Google Scholar
  12. 12.
    C. Meneghini et al., Phys. Rev. B 65, 012111 (2002).ADSCrossRefGoogle Scholar
  13. 13.
    K. H. Kim et al., Phys. Rev. Lett. 81, 1517 (1998).ADSCrossRefGoogle Scholar
  14. 14.
    A. Sacchetti et al., submitted to Phys. Rev. B (2004).Google Scholar
  15. 15.
    E. Dagotto et al., Solid State Commun. 126, 9 (2003).ADSCrossRefGoogle Scholar
  16. 16.
    A. Lanzara et al., Phys. Rev. Lett. 81, 878 (1998).ADSCrossRefGoogle Scholar
  17. 17.
    G. Papavassiliou et al., Phys. Rev. Lett. 84, 761 (2000)ADSCrossRefGoogle Scholar
  18. 18.
    R. H. Heffner et al., Phys. Rev. B 63, 094408 (2001).ADSCrossRefGoogle Scholar
  19. 19.
    M. M. Savosta and P. Novák, Phys. Rev. Lett. 87, 137204 (2001).ADSCrossRefGoogle Scholar
  20. 20.
    K. Takenaka et al., Phys. Rev. B 60, 13011 (1999)ADSCrossRefGoogle Scholar
  21. 21.
    N. Kida et al., Phys. Rev. B 62, R11965 (2000)ADSCrossRefGoogle Scholar
  22. 22.
    C. A. Perroni et al., Phys. Rev. B 64, 144302 (2001).ADSCrossRefGoogle Scholar

Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  • P. Dore
    • 1
  • A. Sacchetti
    • 1
  • P. Postorino
    • 1
  • A. Congeduti
    • 2
  • F. A. Gorelli
    • 3
  • L. Ulivi
    • 3
    • 4
  1. 1.COHERENTIA CNR-INFM and Dipartimento di FisicaUniversita’ di Roma “La Sapienza”RomaItaly
  2. 2.Physique des Milieux Condensés, CNRS-UMR 7602Université Pierre et Marie CurieParis Cedex 05France
  3. 3.INFM and LENSSesto FiorentinoItaly
  4. 4.IFAC-CNRFirenzeItaly

Personalised recommendations