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Title: Synthesis and characterisation of the novel double perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu

Abstract

Highlights: ► La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu perovskites adopt the GdFeO{sub 3} type structure. ► HREM and ED study indicating week ordering of B-cations for B = Mg. ► Antiferromagnetics with T{sub N} 90 (Mg), 125 (Ni) and 140 K (Ni). -- Abstract: The novel perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, and Cu have been synthesised at 1350 °C in air via the citrate route. Rietveld refinements using neutron powder diffraction (NPD) data showed that the compounds adopt the GdFeO{sub 3} type structure with space group Pbnm, and unit cell parameters a≈b≈√(2)×a{sub p} and c ≈ 2 × a{sub p}, where a{sub p} ≈ 3.8 Å. Selected area electron diffraction (SAED) of B = Ni and Cu samples confirmed space group Pbnm. However, distinct reflections forbidden in Pbnm symmetry, but allowed in the monoclinic sub-group P2{sub 1}/n and unit cell parameters a≈b≈√(2)×a{sub p} and c ≈ 2 × a{sub p}, β ≈ 90° were present in SAED patterns of B = Mg sample. This indicates an ordering of the B-cations within the crystal structure of La{sub 2}CrMg{sub 2/3}Nb{sub 1/3}O{sub 6}. High-resolution electron microscopy (HREM) study indicating uniform, without formation of clusters,more » ordering of B-cations in the crystallites of La{sub 2}CrMg{sub 2/3}Nb{sub 1/3}O{sub 6}. Magnetic susceptibility measurements show that the compounds are antiferromagnetic (with some glass or spin clustering effects due to additional ferromagnetic interactions between the B-cations) with T{sub N} for La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu being 90, 125 and 140 K, respectively.« less

Authors:
; ;  [1]; ;  [2];  [3]; ; ; ;  [4]
  1. Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden)
  2. Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden)
  3. ISIS, Rutherford Appleton Laboratory, Didcot OX11 OQX (United Kingdom)
  4. M.V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
22215738
Resource Type:
Journal Article
Journal Name:
Materials Research Bulletin
Additional Journal Information:
Journal Volume: 47; Journal Issue: 9; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0025-5408
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; ANTIFERROMAGNETISM; ELECTRON DIFFRACTION; INORGANIC COMPOUNDS; INTERACTIONS; MAGNETIC SUSCEPTIBILITY; MONOCLINIC LATTICES; NEUTRON DIFFRACTION; ORTHORHOMBIC LATTICES; PEROVSKITES; SPACE GROUPS; SYNTHESIS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION

Citation Formats

Svensson, G., E-mail: gunnar.svensson@mmk.su.se, Grins, J., Shafeie, S., Masson, D., Norberg, S. T., Eriksson, S., Hull, S., Zakharov, K. V., Volkova, O. S., Vasil’ev, A. N., and Istomin, S. Ya. Synthesis and characterisation of the novel double perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu. United States: N. p., 2012. Web. doi:10.1016/J.MATERRESBULL.2012.05.019.
Svensson, G., E-mail: gunnar.svensson@mmk.su.se, Grins, J., Shafeie, S., Masson, D., Norberg, S. T., Eriksson, S., Hull, S., Zakharov, K. V., Volkova, O. S., Vasil’ev, A. N., & Istomin, S. Ya. Synthesis and characterisation of the novel double perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu. United States. https://doi.org/10.1016/J.MATERRESBULL.2012.05.019
Svensson, G., E-mail: gunnar.svensson@mmk.su.se, Grins, J., Shafeie, S., Masson, D., Norberg, S. T., Eriksson, S., Hull, S., Zakharov, K. V., Volkova, O. S., Vasil’ev, A. N., and Istomin, S. Ya. 2012. "Synthesis and characterisation of the novel double perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu". United States. https://doi.org/10.1016/J.MATERRESBULL.2012.05.019.
@article{osti_22215738,
title = {Synthesis and characterisation of the novel double perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu},
author = {Svensson, G., E-mail: gunnar.svensson@mmk.su.se and Grins, J. and Shafeie, S. and Masson, D. and Norberg, S. T. and Eriksson, S. and Hull, S. and Zakharov, K. V. and Volkova, O. S. and Vasil’ev, A. N. and Istomin, S. Ya.},
abstractNote = {Highlights: ► La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu perovskites adopt the GdFeO{sub 3} type structure. ► HREM and ED study indicating week ordering of B-cations for B = Mg. ► Antiferromagnetics with T{sub N} 90 (Mg), 125 (Ni) and 140 K (Ni). -- Abstract: The novel perovskites La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, and Cu have been synthesised at 1350 °C in air via the citrate route. Rietveld refinements using neutron powder diffraction (NPD) data showed that the compounds adopt the GdFeO{sub 3} type structure with space group Pbnm, and unit cell parameters a≈b≈√(2)×a{sub p} and c ≈ 2 × a{sub p}, where a{sub p} ≈ 3.8 Å. Selected area electron diffraction (SAED) of B = Ni and Cu samples confirmed space group Pbnm. However, distinct reflections forbidden in Pbnm symmetry, but allowed in the monoclinic sub-group P2{sub 1}/n and unit cell parameters a≈b≈√(2)×a{sub p} and c ≈ 2 × a{sub p}, β ≈ 90° were present in SAED patterns of B = Mg sample. This indicates an ordering of the B-cations within the crystal structure of La{sub 2}CrMg{sub 2/3}Nb{sub 1/3}O{sub 6}. High-resolution electron microscopy (HREM) study indicating uniform, without formation of clusters, ordering of B-cations in the crystallites of La{sub 2}CrMg{sub 2/3}Nb{sub 1/3}O{sub 6}. Magnetic susceptibility measurements show that the compounds are antiferromagnetic (with some glass or spin clustering effects due to additional ferromagnetic interactions between the B-cations) with T{sub N} for La{sub 2}CrB{sub 2/3}Nb{sub 1/3}O{sub 6}, B = Mg, Ni, Cu being 90, 125 and 140 K, respectively.},
doi = {10.1016/J.MATERRESBULL.2012.05.019},
url = {https://www.osti.gov/biblio/22215738}, journal = {Materials Research Bulletin},
issn = {0025-5408},
number = 9,
volume = 47,
place = {United States},
year = {Sat Sep 15 00:00:00 EDT 2012},
month = {Sat Sep 15 00:00:00 EDT 2012}
}