Coexisting nanoscale inverse spinel and rock salt crystallographic phases in NiCo2O4 epitaxial thin films grown by pulsed laser deposition

H. Sharona; B. Loukya; U. Bhat; R. Sahu; B. Vishal; P. Silwal; A. Gupta; R. Datta

doi:10.1063/1.4998776

Coexisting nanoscale inverse spinel and rock salt crystallographic phases in NiCo₂O₄ epitaxial thin films grown by pulsed laser deposition

H. Sharona, B. Loukya, U. Bhat, R. Sahu, B. Vishal, P. Silwal, A. Gupta, R. Datta^*

^*Corresponding author for this work

Physical Sciences and Engineering

Research output: Contribution to journal › Article › peer-review

17 Scopus citations

Abstract

The origin of alternating wavy dark-bright stripe-like contrast in strain contrast transmission electron microscopy images of NiCo₂O₄ (NCO) epitaxial thin films grown by pulsed laser deposition has been investigated. The nanoscale stripe-like pattern is determined to be associated with coexisting rock salt (RS) and inverse spinel crystal phases. The presence of two different phases, not addressed in previous reports, is experimentally confirmed by both electron diffraction and high resolution transmission electron microscopy imaging. First principles based calculations, together with compressive strain present in the films, support the formation of such coexisting crystallographic phases in NCO. Similar microstructural patterns and RS structure are not observed in epitaxial films of two other oxides of the spinel family, namely, NiFe₂O₄ and CoFe₂O₄. A correlation between the coexisting structures and the macroscopic physical properties of NCO is discussed.

Original language	English (US)
Article number	225301
Journal	Journal of Applied Physics
Volume	122
Issue number	22
DOIs	https://doi.org/10.1063/1.4998776
State	Published - Dec 14 2017

Bibliographical note

Funding Information:
The authors at JNCASR sincerely thank Professor C. N. R. Rao for the Advanced Microscopy Facility and ICMS for the research funding. The work at the University of Alabama was supported by a NSF Grant No. ECCS-1509875.

Publisher Copyright:
© 2017 Author(s).

ASJC Scopus subject areas

General Physics and Astronomy

Access to Document

10.1063/1.4998776

Cite this

@article{c23aa5382aad4fe5ae7aa1627a0f7487,

title = "Coexisting nanoscale inverse spinel and rock salt crystallographic phases in NiCo2O4 epitaxial thin films grown by pulsed laser deposition",

abstract = "The origin of alternating wavy dark-bright stripe-like contrast in strain contrast transmission electron microscopy images of NiCo2O4 (NCO) epitaxial thin films grown by pulsed laser deposition has been investigated. The nanoscale stripe-like pattern is determined to be associated with coexisting rock salt (RS) and inverse spinel crystal phases. The presence of two different phases, not addressed in previous reports, is experimentally confirmed by both electron diffraction and high resolution transmission electron microscopy imaging. First principles based calculations, together with compressive strain present in the films, support the formation of such coexisting crystallographic phases in NCO. Similar microstructural patterns and RS structure are not observed in epitaxial films of two other oxides of the spinel family, namely, NiFe2O4 and CoFe2O4. A correlation between the coexisting structures and the macroscopic physical properties of NCO is discussed.",

author = "H. Sharona and B. Loukya and U. Bhat and R. Sahu and B. Vishal and P. Silwal and A. Gupta and R. Datta",

note = "Funding Information: The authors at JNCASR sincerely thank Professor C. N. R. Rao for the Advanced Microscopy Facility and ICMS for the research funding. The work at the University of Alabama was supported by a NSF Grant No. ECCS-1509875. Publisher Copyright: {\textcopyright} 2017 Author(s).",

year = "2017",

month = dec,

day = "14",

doi = "10.1063/1.4998776",

language = "English (US)",

volume = "122",

journal = "Journal of Applied Physics",

issn = "0021-8979",

publisher = "AIP Publishing",

number = "22",

}

TY - JOUR

T1 - Coexisting nanoscale inverse spinel and rock salt crystallographic phases in NiCo2O4 epitaxial thin films grown by pulsed laser deposition

AU - Sharona, H.

AU - Loukya, B.

AU - Bhat, U.

AU - Sahu, R.

AU - Vishal, B.

AU - Silwal, P.

AU - Gupta, A.

AU - Datta, R.

N1 - Funding Information: The authors at JNCASR sincerely thank Professor C. N. R. Rao for the Advanced Microscopy Facility and ICMS for the research funding. The work at the University of Alabama was supported by a NSF Grant No. ECCS-1509875. Publisher Copyright: © 2017 Author(s).

PY - 2017/12/14

Y1 - 2017/12/14

N2 - The origin of alternating wavy dark-bright stripe-like contrast in strain contrast transmission electron microscopy images of NiCo2O4 (NCO) epitaxial thin films grown by pulsed laser deposition has been investigated. The nanoscale stripe-like pattern is determined to be associated with coexisting rock salt (RS) and inverse spinel crystal phases. The presence of two different phases, not addressed in previous reports, is experimentally confirmed by both electron diffraction and high resolution transmission electron microscopy imaging. First principles based calculations, together with compressive strain present in the films, support the formation of such coexisting crystallographic phases in NCO. Similar microstructural patterns and RS structure are not observed in epitaxial films of two other oxides of the spinel family, namely, NiFe2O4 and CoFe2O4. A correlation between the coexisting structures and the macroscopic physical properties of NCO is discussed.

AB - The origin of alternating wavy dark-bright stripe-like contrast in strain contrast transmission electron microscopy images of NiCo2O4 (NCO) epitaxial thin films grown by pulsed laser deposition has been investigated. The nanoscale stripe-like pattern is determined to be associated with coexisting rock salt (RS) and inverse spinel crystal phases. The presence of two different phases, not addressed in previous reports, is experimentally confirmed by both electron diffraction and high resolution transmission electron microscopy imaging. First principles based calculations, together with compressive strain present in the films, support the formation of such coexisting crystallographic phases in NCO. Similar microstructural patterns and RS structure are not observed in epitaxial films of two other oxides of the spinel family, namely, NiFe2O4 and CoFe2O4. A correlation between the coexisting structures and the macroscopic physical properties of NCO is discussed.

UR - http://www.scopus.com/inward/record.url?scp=85038411121&partnerID=8YFLogxK

U2 - 10.1063/1.4998776

DO - 10.1063/1.4998776

M3 - Article

AN - SCOPUS:85038411121

SN - 0021-8979

VL - 122

JO - Journal of Applied Physics

JF - Journal of Applied Physics

IS - 22

M1 - 225301

ER -