Local spin density functional investigations of the chemical bonding and magnetism in the CMR pyrochlore compound Tl2Mn2O7

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S. F. Matar, M. A. Subramanian and J. Etourneau


Abstract

The electronic and magnetic structures of the ferromagnetic pyrochlore compound Tl2Mn2O7 , exhibiting colossal magnetoresistance (CMR), are self-consistently calculated within the local spin density functional theory using the augmented spherical wave (ASW) method. The influence of mixing between the different l-valence states on the chemical bonding is discussed from the site projected densities of states (DOS) and from the crystal orbital overlap population (COOP). From this a description of the nature of chemical bonding is proposed in relation with the development of the magnetic moment of Mn (2.77 µB) which is found in good agreement with experimental results. Besides, from the calculations a new magnetic property of a weakly half-metallic ferromagnet is proposed.


References

  1. S. Jin, T. H. Tiefel, M. McCormack, R. A. Fastnacht, R. Ramesh and L. H. Chen, Science, 1994, 264, 413 CrossRef CAS.
  2. Y. Shimakawa, Y. Kubo and T. Manako, Nature (London), 1986, 379, 53 CrossRef CAS.
  3. M. A. Subramanian, B. H. Toby, A. P. Ramirez, W. J. Marshall, A. W. Sleight and G. H. Kwei, Science, 1996, 273, 81 CAS.
  4. S.-W. Cheong, H. Y. Hwang, B. Batlogg and L. W. Rupp Jr., Solid State Commun., 1996, 98, 163 CrossRef CAS.
  5. M. A. Subramanian, J. E. Greedan, N. P. Raju, A. P. Ramirez and A. W. Sleight, Proceedings of the ICF7 conference, Bordeaux, September 1996, 1997, in press Search PubMed.
  6. M. A. Subramanian, C. C. Torardi, D. C. Johnson, J. Pannetier and A. W. Sleight, J. Solid State Chem., 1988, 72, 24 CrossRef CAS.
  7. D.-K. Seo, M.-H. Whangbo and M. A. Subramanian, Solid State Commun., 1997, 101, 417 CrossRef CAS.
  8. G. Demazeau, B. Siberchicot, S. F. Matar, C. Gayet and A. Largeteau, J. Appl. Phys., 1994, 75, 8 CrossRef CAS.
  9. S. F. Matar, G. Demazeau, P. Mohn, V. Eyert and S. Najm, Eur. J. Solid State Inorg. Chem., 1994, 31, 615 CAS.
  10. S. F. Matar, A. Villesuzanne and M. Uhl, J. Mater. Chem., 1996, 6, 1785 RSC.
  11. A. R. Williams, J. Kübler and C. D. Gelatt Jr., Phys. Rev. B, 1979, 19, 6094 CrossRef CAS.
  12. W. Kohn and P. Vashishta, in Theory of the Inhomogeneous Electron Gas., ed. S. Lundquist and N. H. March, Plenum, New York, 1983, pp. 79–147 Search PubMed.
  13. J. von Barth and D. Hedin, J. Phys. C, 1972, 5, 1629 CrossRef.
  14. J. F. Janak, Solid State Commun., 1978, 25, 53 CrossRef CAS.
  15. R. Hoffmann and C. Zheng, J. Phys. Chem., 1985, 89, 4175 CrossRef CAS.
  16. (a) V. Eyert, Electronic Structure Calculations for Crystalline Materials in Density Functional Methods: Applications in Chemistry and Materials Science, ed. M. Springborg, Wiley, Chichester, 1997 Search PubMed; (b) V. Eyert and S. F. Matar, 1997, to be published.
  17. E. C. Stoner, Proc. R. Soc. London, 1938, 165, 372 Search PubMed.
  18. K. Schwarz, J. Phys. F: Met. Phys., 1986, 16, L211 CrossRef.
  19. S. F. Matar, G. Demazeau, J. Sticht, V. Eyert and J. Kübler, J. Phys. I France, 1992, 2, 315 Search PubMed.
  20. W. E. Pickett and D. J. Singh, Phys. Rev. B, 1996, 53, 1146 CrossRef CAS.
  21. D. J. Singh, Phys. Rev. B, 1997, 55, 313 CrossRef CAS.
  22. H. Brändle, D. Weller, J. C. Scott, P. M. Oppeneer and G. Güntherodt., Int. J. Mod. Phys. B, 1993, 7, 345 CrossRef.
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