Abstract
The temperature dependence of the nuclear relaxation rates and line shapes of the F{sub O} resonance in the diluted antiferromagnet Fe{sub x} Zn{sub 1-x} F{sub 2} and Mn{sub x} Zn{sub 1-x} F{sub 2} are studied over a large temperature range T{sub N} < {approx} T {<=} 300 K. The high (room) temperature spin-lattice relaxation rates (1/T{sub 1}) of the F{sub O} nuclei, which are not transfer hyperfine coupled to the Fe (or Mn) spins, have been measured and calculated as a function of the concentration x. Good agreement with experiment is found for the theoretical results, which have been obtained in the range 0.1 {<=} x {<=} 0.8. The temperature dependence of 1/T{sub 1} for T{sub N}<=} 300 K was qualitatively understood for both systems. The 1/T{sub 1} data near T{sub N} was used to study Random Field Effects on the critical behavior of Mn{sub .65} Zn{sub .}3{sub 5} F{sub 2}, for fields applied parallel and perpendicular to the easy (C) axis. It was found that the transition temperature T{sub N} depressed substantially with field only for H{sub o} || C. The experimental results are in general accord with the theory for Random Field Effects in disordered, anisotropic antiferromagnets. The
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Citation Formats
Magon, C J.
Nuclear magnetic resonance of randomly diluted magnetic materials; Ressonancia nuclear magnetica em materiais magneticos diluidos aleatoriamente.
Brazil: N. p.,
1985.
Web.
Magon, C J.
Nuclear magnetic resonance of randomly diluted magnetic materials; Ressonancia nuclear magnetica em materiais magneticos diluidos aleatoriamente.
Brazil.
Magon, C J.
1985.
"Nuclear magnetic resonance of randomly diluted magnetic materials; Ressonancia nuclear magnetica em materiais magneticos diluidos aleatoriamente."
Brazil.
@misc{etde_10189948,
title = {Nuclear magnetic resonance of randomly diluted magnetic materials; Ressonancia nuclear magnetica em materiais magneticos diluidos aleatoriamente}
author = {Magon, C J}
abstractNote = {The temperature dependence of the nuclear relaxation rates and line shapes of the F{sub O} resonance in the diluted antiferromagnet Fe{sub x} Zn{sub 1-x} F{sub 2} and Mn{sub x} Zn{sub 1-x} F{sub 2} are studied over a large temperature range T{sub N} < {approx} T {<=} 300 K. The high (room) temperature spin-lattice relaxation rates (1/T{sub 1}) of the F{sub O} nuclei, which are not transfer hyperfine coupled to the Fe (or Mn) spins, have been measured and calculated as a function of the concentration x. Good agreement with experiment is found for the theoretical results, which have been obtained in the range 0.1 {<=} x {<=} 0.8. The temperature dependence of 1/T{sub 1} for T{sub N}<=} 300 K was qualitatively understood for both systems. The 1/T{sub 1} data near T{sub N} was used to study Random Field Effects on the critical behavior of Mn{sub .65} Zn{sub .}3{sub 5} F{sub 2}, for fields applied parallel and perpendicular to the easy (C) axis. It was found that the transition temperature T{sub N} depressed substantially with field only for H{sub o} || C. The experimental results are in general accord with the theory for Random Field Effects in disordered, anisotropic antiferromagnets. The critical divergence of the inhomogeneously broadened F{sub O} NMR was studied in Fe{sub .6} Zn{sub .4} F{sub 2} above T{sub N}. The experimental results agree with Heller`s calculation of the NMR line broadening by Random Field Effects. With H{sub o} || C the line shape changes from Gaussian towards Lozentzian for t < {approx} 10{sup -2} and below T{sub N} its line width increase qualitatively following the increase in the sublattice magnetization. (author).}
place = {Brazil}
year = {1985}
month = {Dec}
}
title = {Nuclear magnetic resonance of randomly diluted magnetic materials; Ressonancia nuclear magnetica em materiais magneticos diluidos aleatoriamente}
author = {Magon, C J}
abstractNote = {The temperature dependence of the nuclear relaxation rates and line shapes of the F{sub O} resonance in the diluted antiferromagnet Fe{sub x} Zn{sub 1-x} F{sub 2} and Mn{sub x} Zn{sub 1-x} F{sub 2} are studied over a large temperature range T{sub N} < {approx} T {<=} 300 K. The high (room) temperature spin-lattice relaxation rates (1/T{sub 1}) of the F{sub O} nuclei, which are not transfer hyperfine coupled to the Fe (or Mn) spins, have been measured and calculated as a function of the concentration x. Good agreement with experiment is found for the theoretical results, which have been obtained in the range 0.1 {<=} x {<=} 0.8. The temperature dependence of 1/T{sub 1} for T{sub N}<=} 300 K was qualitatively understood for both systems. The 1/T{sub 1} data near T{sub N} was used to study Random Field Effects on the critical behavior of Mn{sub .65} Zn{sub .}3{sub 5} F{sub 2}, for fields applied parallel and perpendicular to the easy (C) axis. It was found that the transition temperature T{sub N} depressed substantially with field only for H{sub o} || C. The experimental results are in general accord with the theory for Random Field Effects in disordered, anisotropic antiferromagnets. The critical divergence of the inhomogeneously broadened F{sub O} NMR was studied in Fe{sub .6} Zn{sub .4} F{sub 2} above T{sub N}. The experimental results agree with Heller`s calculation of the NMR line broadening by Random Field Effects. With H{sub o} || C the line shape changes from Gaussian towards Lozentzian for t < {approx} 10{sup -2} and below T{sub N} its line width increase qualitatively following the increase in the sublattice magnetization. (author).}
place = {Brazil}
year = {1985}
month = {Dec}
}