Spin waves throughout the Brillouin zone and magnetic exchange coupling in the ferromagnetic metallic manganites La{sub 1-x}Ca{sub x}MnO{sub 3} (x=0.25,0.30)

Journal Article · Sun Apr 01 00:00:00 EDT 2007 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.75.144408· OSTI ID:20957803

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

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1. Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States)
2. Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200 (United States)
3. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom)
4. Correlated Electron Research Center (CERC), Tsukuba 305-0046 (Japan)

Using time-of-flight and triple-axis inelastic neutron spectroscopy, we determine spin-wave excitations throughout the Brillouin zone for ferromagnetic manganites La{sub 1-x}Ca{sub x}MnO{sub 3} (x=0.25,0.3) in their low-temperature 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 La{sub 0.7}Ca{sub 0.3}MnO{sub 3} are considerably softened in all symmetry directions compared to that of La{sub 0.75}Ca{sub 0.25}MnO{sub 3}. 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.

• OSTI ID: 20957803
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 75, Issue 14; Other Information: DOI: 10.1103/PhysRevB.75.144408; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BRILLOUIN ZONES
CALCIUM COMPOUNDS
COMPARATIVE EVALUATIONS
ELECTRONS
EXCHANGE INTERACTIONS
EXCITATION
FERROMAGNETIC MATERIALS
FLEXIBILITY
HEISENBERG MODEL
LANTHANUM COMPOUNDS
NEUTRON SPECTRA
NEUTRON SPECTROSCOPY
SPIN
SPIN WAVES
TEMPERATURE RANGE 0065-0273 K
TIME-OF-FLIGHT METHOD