Spin waves throughout the Brillouin zone and magnetic exchange coupling in the ferromagnetic metallic manganites La_1−xCa_xMnO₃ (x=0.25, 0.30)

Journal Article · Mon Jan 01 04:00:00 EST 2007 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.75.144408· OSTI ID:931582

Ye, Feng ^[1]; Dai, Pengcheng ^[1]; Fernandez-Baca, Jaime A ^[1]; Adroja, D. T. ^[2]; Perring, T. G. ^[2]; Tomioka, Y. ^[3]; Tokura, Y. ^[4]

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1. ORNL
2. ISIS Facility, Rutherford Appleton Laboratory
3. Correlated Electron Research Center (CERC), Japan
4. University of Tokyo, Tokyo, Japan

Using time-of-flight and triple-axis inelastic neutron spectroscopy, we determine spin-wave excitations throughout the Brillouin zone for ferromagnetic manganites La1−xCaxMnO3 (x=0.25, 0.3) in their lowtemperature metallic states. While spin-wave excitations in the long-wavelength limit spin stiffness D have similar values for both compounds, the excitations near the Brillouin-zone boundary of La0.7Ca0.3MnO3 are considerably softened in all symmetry directions compared to that of La0.75Ca0.25MnO3. A Heisenberg model with the nearest neighbor and the fourth neighbor exchange interactions can describe the overall dispersion curves fairly well. We compare the data with various theoretical models describing the spin excitations of ferromagnetic manganites.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 931582
• Journal Information: Physical Review B, Journal Name: Physical Review B Vol. 75; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BRILLOUIN ZONES
CMR manganite
EXCHANGE INTERACTIONS
FLEXIBILITY
HEISENBERG MODEL
NEUTRON SPECTROSCOPY
SPIN
SPIN WAVES
SYMMETRY
spin wave