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Title: Synthesis, structure and magnetic properties of R-W-O-N (R=Nd and Eu) oxynitrides

Abstract

Neodymium and europium tungsten oxynitrides have been synthesized by the nitridation of corresponding R{sub 2}W{sub 2}O{sub 9} precursor oxides, in ammonia flow at 1173K during 24h. The obtained polycrystalline neodymium oxynitride phase, with NdWO{sub 3.05}N{sub 0.95} composition, crystallizes with the tetragonal symmetry of the scheelite-type structure, space group S.G. I4{sub 1}/a (no. 88). The analogous europium derivative, with formula EuWO{sub 1.58}N{sub 1.42}, presents the cubic perovskite-type structure, S.G. Pm3-bar m (no. 221). Unit-cell parameters, a=5.255(1)A, c=11.399(3)A, and a=3.976(3)A, have been established from Rietveld refinements of collected X-ray powder diffraction patterns for the Nd and Eu- oxynitrides, respectively. Magnetic susceptibility measurements show that NdWO{sub 3.05}N{sub 0.95} behaves as paramagnetic in a wide range of temperature T {approx}50-300K. The downwards deviation from the Curie-Weiss law below 40K reflects the splitting of the {sup 4}I{sub 9/2} ground state of Nd{sup 3+} experienced under the influence of a S{sub 4} crystal field CF potential, as the successful reproduction of the magnetic susceptibility {chi}{sup -1}{sub m} vs. T, using semi-empirical structure-derived CF parameters, indicates. EuWO{sub 1.58}N{sub 1.42} is paramagnetic down to 20K, and the measured effective magnetic moment 8.01{mu}{sub B} is indicative of the presence of Eu{sup 2+} in this oxynitride. The observed sudden jumpmore » in the magnetic susceptibility at 20K and the value of 6{mu}{sub B} for the saturation moment is attributed to the onset of ferrimagnetic interactions in which the Eu{sup 2+} and W{sup 5+} sublattices appear to be involved.« less

Authors:
 [1];  [1];  [2];  [3]
  1. Department of Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain)
  2. Instituto de Ciencia de Materiales de Madrid ICMM, Consejo Superior de Investigaciones Cientificas CSIC, C/ Sor Juana Ines de la Cruz, 3. Cantoblanco, 28040 Madrid (Spain)
  3. Department of Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain), E-mail: rsp92@quim.ucm.es
Publication Date:
OSTI Identifier:
21015623
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 1; Other Information: DOI: 10.1016/j.jssc.2006.09.025; PII: S0022-4596(06)00535-4; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AMMONIA; CRYSTAL FIELD; CUBIC LATTICES; CURIE-WEISS LAW; EUROPIUM COMPOUNDS; EUROPIUM IONS; FERRIMAGNETISM; MAGNETIC MOMENTS; MAGNETIC SUSCEPTIBILITY; NEODYMIUM COMPOUNDS; NEODYMIUM IONS; NITRIDATION; NITRIDES; OXIDES; PARAMAGNETISM; PEROVSKITE; POLYCRYSTALS; SPACE GROUPS; SYNTHESIS; TEMPERATURE RANGE 1000-4000 K; TETRAGONAL LATTICES; TUNGSTEN COMPOUNDS; TUNGSTEN IONS; X-RAY DIFFRACTION

Citation Formats

Pastrana-Fabregas, R., Isasi-Marin, J., Cascales, C., and Saez-Puche, R.. Synthesis, structure and magnetic properties of R-W-O-N (R=Nd and Eu) oxynitrides. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.09.025.
Pastrana-Fabregas, R., Isasi-Marin, J., Cascales, C., & Saez-Puche, R.. Synthesis, structure and magnetic properties of R-W-O-N (R=Nd and Eu) oxynitrides. United States. doi:10.1016/j.jssc.2006.09.025.
Pastrana-Fabregas, R., Isasi-Marin, J., Cascales, C., and Saez-Puche, R.. Mon . "Synthesis, structure and magnetic properties of R-W-O-N (R=Nd and Eu) oxynitrides". United States. doi:10.1016/j.jssc.2006.09.025.
@article{osti_21015623,
title = {Synthesis, structure and magnetic properties of R-W-O-N (R=Nd and Eu) oxynitrides},
author = {Pastrana-Fabregas, R. and Isasi-Marin, J. and Cascales, C. and Saez-Puche, R.},
abstractNote = {Neodymium and europium tungsten oxynitrides have been synthesized by the nitridation of corresponding R{sub 2}W{sub 2}O{sub 9} precursor oxides, in ammonia flow at 1173K during 24h. The obtained polycrystalline neodymium oxynitride phase, with NdWO{sub 3.05}N{sub 0.95} composition, crystallizes with the tetragonal symmetry of the scheelite-type structure, space group S.G. I4{sub 1}/a (no. 88). The analogous europium derivative, with formula EuWO{sub 1.58}N{sub 1.42}, presents the cubic perovskite-type structure, S.G. Pm3-bar m (no. 221). Unit-cell parameters, a=5.255(1)A, c=11.399(3)A, and a=3.976(3)A, have been established from Rietveld refinements of collected X-ray powder diffraction patterns for the Nd and Eu- oxynitrides, respectively. Magnetic susceptibility measurements show that NdWO{sub 3.05}N{sub 0.95} behaves as paramagnetic in a wide range of temperature T {approx}50-300K. The downwards deviation from the Curie-Weiss law below 40K reflects the splitting of the {sup 4}I{sub 9/2} ground state of Nd{sup 3+} experienced under the influence of a S{sub 4} crystal field CF potential, as the successful reproduction of the magnetic susceptibility {chi}{sup -1}{sub m} vs. T, using semi-empirical structure-derived CF parameters, indicates. EuWO{sub 1.58}N{sub 1.42} is paramagnetic down to 20K, and the measured effective magnetic moment 8.01{mu}{sub B} is indicative of the presence of Eu{sup 2+} in this oxynitride. The observed sudden jump in the magnetic susceptibility at 20K and the value of 6{mu}{sub B} for the saturation moment is attributed to the onset of ferrimagnetic interactions in which the Eu{sup 2+} and W{sup 5+} sublattices appear to be involved.},
doi = {10.1016/j.jssc.2006.09.025},
journal = {Journal of Solid State Chemistry},
number = 1,
volume = 180,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}