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Title: Phase relation, crystal structures, and magnetic properties of Nd-Co-B borides

Abstract

The phase relation of the ternary system Nd-Co-B quenched from 600 C in the Co-rich region has been determined by means of X-ray powder diffraction. In this region there exist 11 ternary borides. Five borides are members of the homologous series Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} (or NdCo{sub 5{minus}x}B{sub x}). New layered borides Nd{sub 3}Co{sub 13}B{sub 2} and Nd{sub 5}Co{sub 19}B{sub 6} have not been reported previously. The space group of them is P6/mmm and their crystal structures are refined by the Rietveld method. All the compounds of this Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} family magnetically order between T{sub C} = 710 K for Nd{sub 3}Co{sub 13}B{sub 2} and T{sub C} = 330 K for Nd{sub 2}Co{sub 7}B{sub 3}. The mean cobalt moments of the Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} borides determined at 4.2 K are strongly dependent on the composition. On the basis of the experimental results, three kinds of Co sites with different magnetic moments are proposed. It is shown that increasing B content in NdCo{sub 5{minus}x}B{sub x} borides leads to an increase of the second-order crystal-field parameters A{sub 20}, which explains the enhancement of the magnetocrystalline anisotropy. Spin reorientations are observed in Nd{sub 3}Co{sub 13}B{sub 2} and Nd{sub 3}Co{sub 11}B{submore » 4} compounds. The magnetic phase diagram of the Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} borides is also given, and the behavior of magnetocrystalline anisotropy is analyzed using the single ion model.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Chinese Academy of Sciences, Beijing (CN)
OSTI Identifier:
20080262
Resource Type:
Journal Article
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 12; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 0897-4756
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COBALT BORIDES; NEODYMIUM BORIDES; CRYSTAL STRUCTURE; MAGNETIC PROPERTIES; PHASE DIAGRAMS

Citation Formats

Chen, Y., Li, X., Chen, X.L., Liang, J.K., Rao, G.H., Shen, B.G., Liu, Q.L., Jin, L.P., and Wang, M.Z. Phase relation, crystal structures, and magnetic properties of Nd-Co-B borides. United States: N. p., 2000. Web. doi:10.1021/cm990462f.
Chen, Y., Li, X., Chen, X.L., Liang, J.K., Rao, G.H., Shen, B.G., Liu, Q.L., Jin, L.P., & Wang, M.Z. Phase relation, crystal structures, and magnetic properties of Nd-Co-B borides. United States. doi:10.1021/cm990462f.
Chen, Y., Li, X., Chen, X.L., Liang, J.K., Rao, G.H., Shen, B.G., Liu, Q.L., Jin, L.P., and Wang, M.Z. Mon . "Phase relation, crystal structures, and magnetic properties of Nd-Co-B borides". United States. doi:10.1021/cm990462f.
@article{osti_20080262,
title = {Phase relation, crystal structures, and magnetic properties of Nd-Co-B borides},
author = {Chen, Y. and Li, X. and Chen, X.L. and Liang, J.K. and Rao, G.H. and Shen, B.G. and Liu, Q.L. and Jin, L.P. and Wang, M.Z.},
abstractNote = {The phase relation of the ternary system Nd-Co-B quenched from 600 C in the Co-rich region has been determined by means of X-ray powder diffraction. In this region there exist 11 ternary borides. Five borides are members of the homologous series Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} (or NdCo{sub 5{minus}x}B{sub x}). New layered borides Nd{sub 3}Co{sub 13}B{sub 2} and Nd{sub 5}Co{sub 19}B{sub 6} have not been reported previously. The space group of them is P6/mmm and their crystal structures are refined by the Rietveld method. All the compounds of this Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} family magnetically order between T{sub C} = 710 K for Nd{sub 3}Co{sub 13}B{sub 2} and T{sub C} = 330 K for Nd{sub 2}Co{sub 7}B{sub 3}. The mean cobalt moments of the Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} borides determined at 4.2 K are strongly dependent on the composition. On the basis of the experimental results, three kinds of Co sites with different magnetic moments are proposed. It is shown that increasing B content in NdCo{sub 5{minus}x}B{sub x} borides leads to an increase of the second-order crystal-field parameters A{sub 20}, which explains the enhancement of the magnetocrystalline anisotropy. Spin reorientations are observed in Nd{sub 3}Co{sub 13}B{sub 2} and Nd{sub 3}Co{sub 11}B{sub 4} compounds. The magnetic phase diagram of the Nd{sub m+n}Co{sub 5m+3n}B{sub 2n} borides is also given, and the behavior of magnetocrystalline anisotropy is analyzed using the single ion model.},
doi = {10.1021/cm990462f},
journal = {Chemistry of Materials},
issn = {0897-4756},
number = 5,
volume = 12,
place = {United States},
year = {2000},
month = {5}
}