Low energy spin wave excitations in bilayered magnetic manganite La{sub 2-2x}Sr{sub 1+2x}Mn{sub 2}O{sub 7} (0.30 {<=}{chi}{>=} 0.50).

Journal Article · Sun Jun 01 04:00:00 EDT 2003 · Phys. Rev. B

DOI:https://doi.org/10.1103/PhysRevB.67.214428· OSTI ID:961166

Martinho, H; Rettori, C; Huber, D L; Oseroff, S B; Mitchell, J F

We have studied the low-temperature behavior of the magnetization and specific heat of the bilayered perovskite system La{sub 2-2x}Sr{sub 1+2x}Mn{sub 2}O{sub 7} for 0.30<{approx}x<{approx}0.50. Our analysis reveals that below 30 K the temperature dependence of the magnetization of the ferromagnetic samples, x=0.30, 0.32, and 0.36, in a field of 1 T can be interpreted in terms of the thermal excitations of a two-dimensional gas of ferromagnetic magnons. The specific heat in zero field for these samples, such as for the x=0.50 antiferromagnetic one, is linear with temperature in the range of 1.8K <{approx}T<{approx}10K. This behavior can be also explained by the magnon gas model. By comparing specific heat measurements in zero field with those taken in a field of 9 T we are able to extract the lattice and electronic contributions and determine the in-plane exchange interactions. They are found to be in reasonable agreement with the values inferred from analysis of the magnetization data and also with the values reported by inelastic neutron scattering studies. In addition, we found that the electronic density of states obtained for the x=0.50 sample is in agreement with previous band structure calculations.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; NSF; FOR
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 961166
• Report Number(s): ANL/MSD/JA-45190
• Journal Information: Phys. Rev. B, Journal Name: Phys. Rev. B Journal Issue: 21 ; Jun. 1, 2003 Vol. 67; ISSN 1098-0121
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DENSITY
EXCHANGE INTERACTIONS
MAGNETIZATION
MAGNONS
NEUTRONS
PEROVSKITE
RANGE
SCATTERING
SPECIFIC HEAT
SPIN WAVES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0065-0273 K