Effects of Magnetization on Hole Localization and MnO6 Octahedra Disorder in Hole-Doped Lanthanum Manganese Perovskites
Booth, C. H. ; Bridges, F. ; Neumeier, J. J. ; Brosha, E. L. ; Geballe, T. H. ; Snyder, G. J. ; Kwei, G. H.
Springer
Published 1999
Springer
Published 1999
| ISSN: |
1572-9605
|
|---|---|
| Keywords: |
X-ray-absorption fine-structure (XAFS) ; “colossal” magnetoresistance (CMR) ; Jahn–Teller polarons ; La1−x A x MnO3 ; La1−y MnO3+δ
|
| Source: |
Springer Online Journal Archives 1860-2000
|
| Topics: |
Electrical Engineering, Measurement and Control Technology
Physics
|
| Notes: |
Abstract We review the distortions of the MnO6 octahedra reduced by magnetization in hole-doped lanthanum manganese perovskites. The systems we consider include the “colossal” magnetoresistance (CMR) samples La1−x Ca x MnO3 (x=0.21, 0.25, 0.30), La0.67Ba0.33MnO3, and a poorer quality La0.67Pb0.33MnO3 sample. We also report preliminary work on three samples of oxygen-doped LaMnO3+δ and a lanthanum-deficient La0.9MnO3 sample. We find the same exponential relationship between the removal of the distortion and the sample magnetization in the Ba- and Pb-doped CMR samples as was found previously for the Ca-doped samples. The MnO6 distortion in the oxygen-doped materials is found to slightly reduce below the magnetic transition, although much less so than in the CMR samples. Above T c, the antiferromagnetic LaMnO3.006 sample shows a softer temperature dependence of the Mn–O bond length distribution broadening. Surprisingly, even this sample shows deviations from thermal (Debye) behavior near T N, possibly due to FM coupling within MnO planes.
|
| Type of Medium: |
Electronic Resource
|
| URL: |