Lattice effect in perovskite and pyrochlore CMR materials
- Los Alamos National Lab., NM (United States)
- Michigan State Univ., East Lansing, MI (United States)
- Bell Labs., Murray Hill, NJ (United States)
- Du Pont de Nemours (E.I.) and Co., Wilmington, DE (United States). Central Research and Development Dept.
Colossal magnetoresistance (CMR) in doped La manganite thin films (La{sub 1-x}M{sub x}MnO{sub 3}, where M = divalent ion, either Ca or Pb) has been shown to result in a factor of 10{sup 6} suppression of the resistance. The driving force for the CMR transition is thought to be the double-exchange interaction. Many studies of both the crystal structure and the local structure of the La{sub 1-x}M{sub x}MnO{sub 3} (M = Ca, Sr, Ba, Pb) system have now been carried out. As expected, these systems all show a strong coupling of the lattice to the CMR transition. On the other hand, neutron diffraction and x-ray absorption for the Tl{sub 2}Mn{sub 2}O{sub 7} pyrochlore, which also exhibits CMR, shows no deviations from ideal stoichiometry, mixed valency, or Jahn-Teller distortions of the MnO{sub 6} octahedron. We present results of crystallographic and local structural studies of these two important classes of CMR materials, compare the differences in structural response, and discuss the implications of these findings to our understanding of these materials.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36; W-7405-ENG-48
- OSTI ID:
- 521540
- Report Number(s):
- LA-UR-97-1360; CONF-970302-22; ON: DE97007742
- Resource Relation:
- Conference: Spring meeting of the Materials Research Society, San Francisco, CA (United States), 31 Mar - 4 Apr 1997; Other Information: PBD: [1997]
- Country of Publication:
- United States
- Language:
- English
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