A mean field theory of magnets with competing double exchange and superexchange interactions

Journal Article · Mon Jun 01 04:00:00 EDT 1998 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.367798· OSTI ID:624865

Golosov, D I ^[1]; Norman, M R ^[2]; Levin, K ^[1]

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1. The James Franck Institute, The University of Chicago, 5640 S. Ellis Avenue, Chicago, Illinois60637 (United States)
2. Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois60439 (United States)

We study the competition between ferromagnetic double exchange (DE) and direct nearest-neighbor antiferromagnetic exchange J{sub AF} in two-dimensional colossal magnetoresistance materials. Towards this end, a single site mean field theory is proposed which incorporates the hopping-mediated nature of the DE contribution. The canted state appears only under highly restricted conditions. Instead, in the regime where the antiferromagnetic and DE ferromagnetic interactions are of comparable scale (and in the classical limit), the system exhibits ferro- or antiferromagnetic order with incomplete saturation of the lattice or sublattice magnetization. We interpret these results as an indication that spin fluctuations remain strong even at low temperatures and discuss the associated experimental implications. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 624865
• Report Number(s): CONF-980102--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 83; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETISM
EXCHANGE INTERACTIONS
LANTHANUM OXIDES
MAGNETIZATION
MAGNETORESISTANCE
MANGANESE OXIDES
SPIN FLIP
STRONTIUM OXIDES