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Title: Spin dynamics and absence of a central peak anomaly in La{sub 0.67}Ca{sub 0.33}MnO{sub 3}

Abstract

Low-angle inelastic neutron scattering was used to study the temperature and wave vector dependence of the spin waves in La{sub 0.67}Ca{sub 0.33}MnO{sub 3} perovskite-based colossal magnetoresistance material. At low q the spin waves show Heisenberg ferromagnetic dispersion (E=Dq{sup 2}+{delta}) where D is the spin stiffness, q is the wave vector, and {delta} is the energy gap. However, the temperature renormalization of the spin stiffness D is anomalous, and as T increases toward T{sub c}, D does not show the expected power law collapse, but rather exhibits a sudden sharp drop suggestive of a first-order phase transition. Detailed neutron measurements of the order parameter in zero applied field showed a similar first-order-like transition. However, no temperature hysteresis was observed in either D or in the magnetization. (c) 2000 American Institute of Physics.

Authors:
 [1];  [1];  [1];  [2];  [2];  [3]
  1. Physics Department, University of Missouri, Columbia, Missouri 65211 (United States)
  2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  3. Department of Physics, Texas A and M University-Commerce, Commerce, Texas 75429 (United States)
Publication Date:
OSTI Identifier:
20216249
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 87; Journal Issue: 9; Other Information: PBD: 1 May 2000; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LANTHANUM OXIDES; CALCIUM OXIDES; MANGANESE OXIDES; SPIN WAVES; NEUTRON DIFFRACTION; INELASTIC SCATTERING; PEROVSKITES; DISPERSION RELATIONS; ORDER PARAMETERS; PHASE TRANSFORMATIONS; EXPERIMENTAL DATA

Citation Formats

Rhyne, J. J., Kaiser, H., Stumpe, L., Mitchell, J. F., McCloskey, T., and Chourasia, A. R. Spin dynamics and absence of a central peak anomaly in La{sub 0.67}Ca{sub 0.33}MnO{sub 3}. United States: N. p., 2000. Web. doi:10.1063/1.372531.
Rhyne, J. J., Kaiser, H., Stumpe, L., Mitchell, J. F., McCloskey, T., & Chourasia, A. R. Spin dynamics and absence of a central peak anomaly in La{sub 0.67}Ca{sub 0.33}MnO{sub 3}. United States. doi:10.1063/1.372531.
Rhyne, J. J., Kaiser, H., Stumpe, L., Mitchell, J. F., McCloskey, T., and Chourasia, A. R. Mon . "Spin dynamics and absence of a central peak anomaly in La{sub 0.67}Ca{sub 0.33}MnO{sub 3}". United States. doi:10.1063/1.372531.
@article{osti_20216249,
title = {Spin dynamics and absence of a central peak anomaly in La{sub 0.67}Ca{sub 0.33}MnO{sub 3}},
author = {Rhyne, J. J. and Kaiser, H. and Stumpe, L. and Mitchell, J. F. and McCloskey, T. and Chourasia, A. R.},
abstractNote = {Low-angle inelastic neutron scattering was used to study the temperature and wave vector dependence of the spin waves in La{sub 0.67}Ca{sub 0.33}MnO{sub 3} perovskite-based colossal magnetoresistance material. At low q the spin waves show Heisenberg ferromagnetic dispersion (E=Dq{sup 2}+{delta}) where D is the spin stiffness, q is the wave vector, and {delta} is the energy gap. However, the temperature renormalization of the spin stiffness D is anomalous, and as T increases toward T{sub c}, D does not show the expected power law collapse, but rather exhibits a sudden sharp drop suggestive of a first-order phase transition. Detailed neutron measurements of the order parameter in zero applied field showed a similar first-order-like transition. However, no temperature hysteresis was observed in either D or in the magnetization. (c) 2000 American Institute of Physics.},
doi = {10.1063/1.372531},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 9,
volume = 87,
place = {United States},
year = {2000},
month = {5}
}