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Title: MnO spin-wave dispersion curves from neutron powder diffraction

Abstract

We describe a model-independent approach for the extraction of spin-wave dispersion curves from powder neutron total scattering data. Our approach is based on a statistical analysis of real-space spin configurations to calculate spin-dynamical quantities. The RMCPROFILE implementation of the reverse Monte Carlo refinement process is used to generate a large ensemble of supercell spin configurations from MnO powder diffraction data collected at 100 K. Our analysis of these configurations gives spin-wave dispersion curves for MnO that agree well with those determined independently using neutron triple-axis spectroscopic techniques.

Authors:
;  [1];  [2];  [2];  [3]
  1. Department of Earth Sciences, Cambridge University, Downing Street, Cambridge CB2 3EQ (United Kingdom)
  2. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)
  3. (United Kingdom)
Publication Date:
OSTI Identifier:
20976705
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 7; Other Information: DOI: 10.1103/PhysRevB.75.075423; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; DIAGRAMS; DISPERSIONS; MANGANESE OXIDES; MONTE CARLO METHOD; NEUTRON DIFFRACTION; NEUTRONS; POWDERS; SPIN; SPIN WAVES

Citation Formats

Goodwin, Andrew L., Dove, Martin T., Tucker, Matthew G., Keen, David A., and Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, Oxford OX1 3PU. MnO spin-wave dispersion curves from neutron powder diffraction. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.075423.
Goodwin, Andrew L., Dove, Martin T., Tucker, Matthew G., Keen, David A., & Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, Oxford OX1 3PU. MnO spin-wave dispersion curves from neutron powder diffraction. United States. doi:10.1103/PHYSREVB.75.075423.
Goodwin, Andrew L., Dove, Martin T., Tucker, Matthew G., Keen, David A., and Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, Oxford OX1 3PU. Thu . "MnO spin-wave dispersion curves from neutron powder diffraction". United States. doi:10.1103/PHYSREVB.75.075423.
@article{osti_20976705,
title = {MnO spin-wave dispersion curves from neutron powder diffraction},
author = {Goodwin, Andrew L. and Dove, Martin T. and Tucker, Matthew G. and Keen, David A. and Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, Oxford OX1 3PU},
abstractNote = {We describe a model-independent approach for the extraction of spin-wave dispersion curves from powder neutron total scattering data. Our approach is based on a statistical analysis of real-space spin configurations to calculate spin-dynamical quantities. The RMCPROFILE implementation of the reverse Monte Carlo refinement process is used to generate a large ensemble of supercell spin configurations from MnO powder diffraction data collected at 100 K. Our analysis of these configurations gives spin-wave dispersion curves for MnO that agree well with those determined independently using neutron triple-axis spectroscopic techniques.},
doi = {10.1103/PHYSREVB.75.075423},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 7,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} have been investigated between 5 K and 300 K by means of high resolution neutron powder diffraction followed by Rietveld refinement and dc magnetic measurements. During cooling orbital ordering at the Mn sub-lattice takes place at T{sub OO}{approx}280 K in both compounds, inducing an orthorhombic to monoclinic phase transition. As the temperature is further decreased an antiferromagnetic CE-type structure occurs in both compounds at T{sub N}{approx}105 K. The comparison with other (Ln{sub 0.50}Ca{sub 0.50})MnO{sub 3} compounds reveals that at room temperature the average Jahn-Teller distortionmore » increases sharply with the decrease of the ionic radius for lanthanides heavier than Sm. The ordered magnetic moment progressively decreases as the lanthanide ionic radius decreases on account of the decreased values of the Mn-O-Mn bond angles. - Graphical abstract: Rietveld refinement plot for (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} obtained from neutron powder diffraction data collected at 5 K; the inset shows the CE-type spin ordering taking place at the Mn sub-lattice. Highlights: Black-Right-Pointing-Pointer The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} were analyzed by neutron powder diffraction. Black-Right-Pointing-Pointer Orbital ordering takes place below T{sub OO}{approx}280 K in both compounds. Black-Right-Pointing-Pointer An antiferromagnetic CE-type structure occurs in both compounds below T{sub N}{approx}105 K. Black-Right-Pointing-Pointer A Comparison with other (Ln{sub 0.50}Ca{sub 0.50})MnO{sub 3} compounds is reported.« less
  • No abstract prepared.
  • The results of neutron diffraction studies of the effect of the isotopic substitution {sup 16}O {yields} {sup 18}O in Sm{sub 1-x}Sr{sub x}MnO{sub 3}-type (x = 0.45 and 0.50) manganites are considered. The parameters of the crystal and magnetic structures of the samples are determined in the temperature range 1.4-300.0 K. It is shown that the isotopic substitution considerably changes the phase diagram of manganites. The results of the earlier macroscopic studies of the same samples are confirmed.