Structural effects on the magnetic and transport properties of perovskite A{sub 1{minus}x}A{sub x}{sup {prime}}MnO{sub 3} (x=0.25, 0.30)
- MASPEC-CNR, via Chiavari 18A, 43100 Parma (Italy)
- Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974 (United States)
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
The evolution of the structural properties of A{sub 1{minus}x}A{sub x}{sup {prime}}MnO{sub 3} was determined as a function of temperature, average A-site radius {l_angle}r{sub A}{r_angle}, and applied pressure for the {open_quotes}optimal{close_quotes} doping range x=0.25, 0.30, by using high-resolution neutron powder diffraction. The metal-insulator transition, which can be induced both as a function of temperature and of {l_angle}r{sub A}{r_angle}, was found to be accompanied by significant structural changes. Both the paramagnetic charge-localized phase, which exists at high temperatures for all values of {l_angle}r{sub A}{r_angle}, and the spin-canted ferromagnetic charge-ordered phase, which is found at low temperatures for low values of {l_angle}r{sub A}{r_angle}, are characterized by large metric distortions of the MnO{sub 6} octahedra. These structural distortions are mainly incoherent with respect to the space-group symmetry, with a significant coherent component only at low {l_angle}r{sub A}{r_angle}. These distortions decrease abruptly at the transition into the ferromagnetic metal phase. These observations are consistent with the hypothesis that, in the insulating phases, lattice distortions of the Jahn-Teller type, in addition to spin scattering, provide a charge-localization mechanism. The evolution of the average structural parameters indicates that the variation of the electronic bandwidth is the driving force for the evolution of the insulator-to-metal transition at T{sub C} as a function of {open_quotes}chemical{close_quotes} and applied pressure. {copyright} {ital 1997} {ital The American Physical Society}
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 664871
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 13 Vol. 56; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
Similar Records
Cation size-temperature phase diagram of the manganites Ln{sub 0.5}Sr{sub 0.5}MnO{sub 3}
Structural changes and related effects due to charge ordering in Nd{sub 0.5}Ca{sub 0.5}MnO{sub 3}