Static and dynamic double-exchange effects in doped manganites

Journal Article · Sun Nov 15 04:00:00 EST 2009 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776109110090· OSTI ID:21443667

Khutsishvili, K O

It is shown that antiferromagnetic ordering in doped manganites with strong double-exchange interaction is transformed into ferromagnetic canted ordering with residual antiferromagnetic behavior in the basal plane as a result of hopping of mobile electron. The canting angle between the core magnetiztions is controlled by the competition of the Heisenberg antiferromagnetic exchange and double exchange. The temperatures of the paramagnet-antiferromagnet and paramagnet-canted ferromagnetic phase transitions are calculated. The results on the dependence of the magnetization in the canted phase and critical temperatures on the doping degree are in qualitative agreement with experiment. The form of uniform oscillations of core magnetiztions in the canted ferromagnetic phase of a doped manganite sample with hopping conduction is analyzed with and without allowance for relaxation of mobile electrons to the lattice. We propose a mechanism for the ferromagnetic resonance broadening and its resonance frequency shift in a ferromagnetic conducting sample (hopping conduction) of doped manganite due to double exchange. The resonance frequency shift and the ferromagnetic resonance damping constant (linewidth) are calculated in this model. In contrast to other relaxation mechanisms, the model is based on the fact that mobile electrons rapidly relax to the lattice (over a time on the order of the precession period).

• OSTI ID: 21443667
• Journal Information: Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 5 Vol. 109; ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
CRITICAL TEMPERATURE
CRYSTAL MODELS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONS
ELEMENTARY PARTICLES
EXCHANGE INTERACTIONS
FERMIONS
FERROMAGNETIC RESONANCE
FERROMAGNETISM
HEISENBERG MODEL
INTERACTIONS
LEPTONS
MAGNETIC RESONANCE
MAGNETISM
MAGNETIZATION
MANGANATES
MANGANESE COMPOUNDS
MATERIALS
MATHEMATICAL MODELS
OSCILLATIONS
OXYGEN COMPOUNDS
PARAMAGNETISM
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RELAXATION
RESONANCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE