Coherent waves of magnetic polarons propagating in La{sub 1{minus}x}Ca{sub x}MnO{sub 3}: An inelastic-neutron-scattering study
- Laboratoire Leon Brillouin, CEA-CNRS, CE Saclay, 91191 Gif sur Yvette Cedex (France)
- Laboratoire de Chimie des Solides, Universite Paris-Sud, 91405 Orsay Cedex (France)
Inelastic neutron scattering has been performed on semiconducting La{sub 1{minus}x}Ca{sub x}MnO{sub 3} single crystals, which exhibit a slightly canted magnetic structure at a low doping rate (x=0.05,0.08). The dynamic study reveals the coexistence of two excitation branches with very different characteristics, and local modes for x=0.05. The first branch is anisotropically dispersed and is readily attributed to spin waves; the Mn spins are coupled by exchange forces, indicating a strong decrease of the antiferromagnetic interplane coupling by doping. The second branch is weakly and isotropically dispersed, which suggests a coupling induced by the hole hopping. Its unusual q-dependent intensity reveals that this excitation is associated with a very short ferromagnetic correlation length ({approx}8{endash}10 {Angstrom}), reminiscent of a picture of mobile {open_quotes}magnetic polarons.{close_quotes} {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 531841
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 2; Other Information: PBD: Jul 1997
- Country of Publication:
- United States
- Language:
- English
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