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Title: Spin dynamics in perovskites, pyrochlores, and layered manganites

Abstract

High temperature electron spin resonance (ESR) and magnetic susceptibility ({chi}) are analyzed for manganites related with colossal magnetoresistance (CMR). The properties of compounds with different crystalline structures: three-dimensional (3D) perovskites, pyrochlore, and La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}, a two-dimensional layer, are compared. In the paramagnetic regime, and outside the critical regions associated with phase transitions, the temperature dependence of the ESR linewidth presents a universal behavior dominated by the variations of {chi}(T), {delta}H{sub pp}(T)=[C/T{chi}(T)]{delta}H{sub pp}({infinity}). The high temperature limit of the linewidth, {delta}H{sub pp}({infinity}), is related to the parameters of the Hamiltonian describing the interactions of the spin system. The role played by magnetic anisotropy, isotropic superexchange, and double exchange is revealed and discussed in the analysis of the experimental data. In CMR and non-CMR pyrochlores, {delta}H{sub pp}({infinity}){proportional_to}{omega}{sub p}{sup 2}/J where J is proportional to the Curie-Weiss temperature, including the hybridization mechanism producing CMR. Instead, {delta}H{sub pp}({infinity}) of CMR perovskites seems not to be affected by the double-exchange interaction. In contrast with the 3D perovskites, the ESR linewidth and resonance field of La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}, a bilayer compound, although isotropic at high temperatures, becomes anisotropic for T{sub c}=125 K<T<T{sub p}{approx_equal}450 K. (c) 2000 American Institute of Physics.

Authors:
 [1];  [2];  [2];  [2];  [3];  [4];  [4];  [4];  [5];  [6]
  1. San Diego State University, San Diego, California 29182-8062 (United States)
  2. Instituto de Fisica ''Gleb Wataghin'' UNICAMP, Campinas, Sao Paulo 13083-970, (Brazil)
  3. University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
  4. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
  5. Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche, (Argentina)
  6. Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche, (Argentina) (and others)
Publication Date:
OSTI Identifier:
20216248
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; PEROVSKITES; PYROCHLORE; LANTHANUM OXIDES; STRONTIUM OXIDES; MANGANESE OXIDES; MAGNETIC SUSCEPTIBILITY; ELECTRON SPIN RESONANCE; TEMPERATURE DEPENDENCE; CURIE-WEISS LAW; EXCHANGE INTERACTIONS; ANISOTROPY; EXPERIMENTAL DATA

Citation Formats

Oseroff, S. B., Moreno, N. O., Pagliuso, P. G., Rettori, C., Huber, D. L., Gardner, J. S., Sarrao, J. L., Thompson, J. D., Causa, M. T., and Alejandro, G. Spin dynamics in perovskites, pyrochlores, and layered manganites. United States: N. p., 2000. Web. doi:10.1063/1.372530.
Oseroff, S. B., Moreno, N. O., Pagliuso, P. G., Rettori, C., Huber, D. L., Gardner, J. S., Sarrao, J. L., Thompson, J. D., Causa, M. T., & Alejandro, G. Spin dynamics in perovskites, pyrochlores, and layered manganites. United States. doi:10.1063/1.372530.
Oseroff, S. B., Moreno, N. O., Pagliuso, P. G., Rettori, C., Huber, D. L., Gardner, J. S., Sarrao, J. L., Thompson, J. D., Causa, M. T., and Alejandro, G. Mon . "Spin dynamics in perovskites, pyrochlores, and layered manganites". United States. doi:10.1063/1.372530.
@article{osti_20216248,
title = {Spin dynamics in perovskites, pyrochlores, and layered manganites},
author = {Oseroff, S. B. and Moreno, N. O. and Pagliuso, P. G. and Rettori, C. and Huber, D. L. and Gardner, J. S. and Sarrao, J. L. and Thompson, J. D. and Causa, M. T. and Alejandro, G.},
abstractNote = {High temperature electron spin resonance (ESR) and magnetic susceptibility ({chi}) are analyzed for manganites related with colossal magnetoresistance (CMR). The properties of compounds with different crystalline structures: three-dimensional (3D) perovskites, pyrochlore, and La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}, a two-dimensional layer, are compared. In the paramagnetic regime, and outside the critical regions associated with phase transitions, the temperature dependence of the ESR linewidth presents a universal behavior dominated by the variations of {chi}(T), {delta}H{sub pp}(T)=[C/T{chi}(T)]{delta}H{sub pp}({infinity}). The high temperature limit of the linewidth, {delta}H{sub pp}({infinity}), is related to the parameters of the Hamiltonian describing the interactions of the spin system. The role played by magnetic anisotropy, isotropic superexchange, and double exchange is revealed and discussed in the analysis of the experimental data. In CMR and non-CMR pyrochlores, {delta}H{sub pp}({infinity}){proportional_to}{omega}{sub p}{sup 2}/J where J is proportional to the Curie-Weiss temperature, including the hybridization mechanism producing CMR. Instead, {delta}H{sub pp}({infinity}) of CMR perovskites seems not to be affected by the double-exchange interaction. In contrast with the 3D perovskites, the ESR linewidth and resonance field of La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}, a bilayer compound, although isotropic at high temperatures, becomes anisotropic for T{sub c}=125 K<T<T{sub p}{approx_equal}450 K. (c) 2000 American Institute of Physics.},
doi = {10.1063/1.372530},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 9,
volume = 87,
place = {United States},
year = {2000},
month = {5}
}