Evidence for a Purely Double-Exchange Mechanism for the Anisotropic Conductivities in Layered La-Sr-Mn-O Single Crystals Below TC

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dc.creatorLi, Q. A.
dc.creatorGray, K. E.
dc.creatorMitchell, J. F.
dc.creatorBerger, A.
dc.creatorOsgood, R.
dc.date1999-03-31
dc.date.accessioned2026-07-07T03:13:09Z
dc.date.available2026-07-07T03:13:09Z
dc.descriptionExperimental evidence supports the double-exchange (DE) mechanism for both in-plane and c-axis conductivity in the colossal-magnetoresistive (CMR) layered manganite La1.4Sr1.6Mn2O7. Below TC, the data determine both the DE and antiferromagnetic (AF) superexchange between bilayers. These agree with recent spin-wave data, such that the ratio of intra- to inter-bilayer DE constants is very close to the spin-independent conductance anisotropy of ~300. The conductivity is shown to be proportional to the square of the measured magnetization over a wide range of fields and for temperatures below the in-plane ferromagnetic ordering temperature, TC. This dependence is shown to be consistent with DE coupling and earlier zero-field studies of La1.2Sr1.8Mn2O7 near TC, which used neutron scattering for the local magnetization. A mixed AF and spin-flop state (similar to the intermediate state of type-I superconductors) is a rigorous prediction of the data and modeling.
dc.description20 pages, 6 figures
dc.identifierhttps://arxiv.org/abs/cond-mat/9903452
dc.identifierhttp://arxiv.org/abs/cond-mat/9903452
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/29187
dc.subjectCondensed Matter
dc.titleEvidence for a Purely Double-Exchange Mechanism for the Anisotropic Conductivities in Layered La-Sr-Mn-O Single Crystals Below TC
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