Ni-substitution induced inversion in znfe2o4 seen by positron annihilation

P. M.G. Nambissan; O. Mondal; S. Chakrabarty; M. Pal

doi:10.4028/www.scientific.net/msf.733.219

Ni-substitution induced inversion in znfe₂o₄ seen by positron annihilation

P. M.G. Nambissan, O. Mondal, S. Chakrabarty, M. Pal

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

8 Scopus citations

Abstract

We report in this work about the inversion of the spinel structure of ZnFe₂O₄ induced by the substitution of Zn²⁺ by Ni²⁺ ions. Positron lifetimes were measured in Zn_1-xNi_xFe₂O₄ with different concentrations (x) of Ni²⁺ ions and a drastic change across x = 0.4 - 0.6 was observed, which is attributed to this transformation. The interchange of positions of the cations on doping leaves a fraction of them unoccupied and these vacancies act as positron trapping centres. Since Ni²⁺ is smaller in size than Zn²⁺, defects due to non-stoichiometry are less in NiFe₂O₄ than in ZnFe₂O₄. The increase in positron lifetime implies the trapping of positrons being shifted from A-to B-sites and is an indication of the transformation from inverse to normal spinel configuration. Coincidence Doppler broadening measurements supported these findings.

Original language	English
Title of host publication	Positron and Positronium Chemistry X
Publisher	Trans Tech Publications Ltd
Pages	219-223
Number of pages	5
ISBN (Print)	9783037855188
DOIs	https://doi.org/10.4028/www.scientific.net/msf.733.219
State	Published - 2013
Externally published	Yes
Event	10th International Workshop on Positron and Positronium Chemistry, PPC-10 - Smolenice Castle, Slovakia Duration: 5 Sep 2011 → 9 Sep 2011

Publication series

Name	Materials Science Forum
Volume	733
ISSN (Print)	0255-5476
ISSN (Electronic)	1662-9752

Conference

Conference	10th International Workshop on Positron and Positronium Chemistry, PPC-10
Country/Territory	Slovakia
City	Smolenice Castle
Period	5/09/11 → 9/09/11

Keywords

Defects
Ferrites
Inversion
Nanocrystals
Positron annihilation
Spinel structure

Access to Document

10.4028/www.scientific.net/msf.733.219

Cite this

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title = "Ni-substitution induced inversion in znfe2o4 seen by positron annihilation",

abstract = "We report in this work about the inversion of the spinel structure of ZnFe2O4 induced by the substitution of Zn2+ by Ni2+ ions. Positron lifetimes were measured in Zn1-xNixFe2O4 with different concentrations (x) of Ni2+ ions and a drastic change across x = 0.4 - 0.6 was observed, which is attributed to this transformation. The interchange of positions of the cations on doping leaves a fraction of them unoccupied and these vacancies act as positron trapping centres. Since Ni2+ is smaller in size than Zn2+, defects due to non-stoichiometry are less in NiFe2O4 than in ZnFe2O4. The increase in positron lifetime implies the trapping of positrons being shifted from A-to B-sites and is an indication of the transformation from inverse to normal spinel configuration. Coincidence Doppler broadening measurements supported these findings.",

keywords = "Defects, Ferrites, Inversion, Nanocrystals, Positron annihilation, Spinel structure",

author = "Nambissan, {P. M.G.} and O. Mondal and S. Chakrabarty and M. Pal",

year = "2013",

doi = "10.4028/www.scientific.net/msf.733.219",

language = "אנגלית",

isbn = "9783037855188",

series = "Materials Science Forum",

publisher = "Trans Tech Publications Ltd",

pages = "219--223",

booktitle = "Positron and Positronium Chemistry X",

note = "10th International Workshop on Positron and Positronium Chemistry, PPC-10 ; Conference date: 05-09-2011 Through 09-09-2011",

}

Nambissan, PMG, Mondal, O, Chakrabarty, S & Pal, M 2013, Ni-substitution induced inversion in znfe₂o₄ seen by positron annihilation. in Positron and Positronium Chemistry X. Materials Science Forum, vol. 733, Trans Tech Publications Ltd, pp. 219-223, 10th International Workshop on Positron and Positronium Chemistry, PPC-10, Smolenice Castle, Slovakia, 5/09/11. https://doi.org/10.4028/www.scientific.net/msf.733.219

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AU - Mondal, O.

AU - Chakrabarty, S.

AU - Pal, M.

PY - 2013

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N2 - We report in this work about the inversion of the spinel structure of ZnFe2O4 induced by the substitution of Zn2+ by Ni2+ ions. Positron lifetimes were measured in Zn1-xNixFe2O4 with different concentrations (x) of Ni2+ ions and a drastic change across x = 0.4 - 0.6 was observed, which is attributed to this transformation. The interchange of positions of the cations on doping leaves a fraction of them unoccupied and these vacancies act as positron trapping centres. Since Ni2+ is smaller in size than Zn2+, defects due to non-stoichiometry are less in NiFe2O4 than in ZnFe2O4. The increase in positron lifetime implies the trapping of positrons being shifted from A-to B-sites and is an indication of the transformation from inverse to normal spinel configuration. Coincidence Doppler broadening measurements supported these findings.

AB - We report in this work about the inversion of the spinel structure of ZnFe2O4 induced by the substitution of Zn2+ by Ni2+ ions. Positron lifetimes were measured in Zn1-xNixFe2O4 with different concentrations (x) of Ni2+ ions and a drastic change across x = 0.4 - 0.6 was observed, which is attributed to this transformation. The interchange of positions of the cations on doping leaves a fraction of them unoccupied and these vacancies act as positron trapping centres. Since Ni2+ is smaller in size than Zn2+, defects due to non-stoichiometry are less in NiFe2O4 than in ZnFe2O4. The increase in positron lifetime implies the trapping of positrons being shifted from A-to B-sites and is an indication of the transformation from inverse to normal spinel configuration. Coincidence Doppler broadening measurements supported these findings.

KW - Defects

KW - Ferrites

KW - Inversion

KW - Nanocrystals

KW - Positron annihilation

KW - Spinel structure

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