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Nature of low-temperature phase transitions in CaMn7O12

  • O. Volkova
  • Yu. Arango
  • N. Tristan
  • V. Kataev
  • E. Gudilin
  • D. Meier
  • T. Lorenz
  • B. Büchner
  • A. Vasil’ev
Condensed Matter

Abstract

New data on the specific heat, thermal expansion, and magnetization of the CaMn7O12 phase require a revision of the current concepts of the sequence of phase transitions in this compound. It is found that a spin-glass phase transition occurs in CaMn7O12 at T M = 49 K, whereas the transition at T S = 89 K exhibits the features of a first-order phase transition and thereby is apparently of structural origin. In the range T M < T< T S , the CaMn7O12 compound exhibits negative thermal expansion, which is also indicative of structural changes.

PACS numbers

65.40.−b 75.47.Lx 

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Copyright information

© Pleiades Publishing, Inc. 2005

Authors and Affiliations

  • O. Volkova
    • 1
  • Yu. Arango
    • 2
  • N. Tristan
    • 2
  • V. Kataev
    • 2
  • E. Gudilin
    • 1
  • D. Meier
    • 3
  • T. Lorenz
    • 3
  • B. Büchner
    • 2
  • A. Vasil’ev
    • 1
  1. 1.Moscow State UniversityVorob’evy gory, MoscowRussia
  2. 2.Leibniz Institute for Solid State and Materials ResearchDresdenGermany
  3. 3.Institute of Physics IIUniversity of CologneCologneGermany

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