skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Temperature-dependent XRD, IR, magnetic, SEM and TEM studies of Jahn–Teller distorted NiCr{sub 2}O{sub 4} powders

Abstract

In the present work we report detailed structural, magnetic and phonon properties of NiCr{sub 2}O{sub 4} powders synthesized via a simple coprecipitation method. Temperature-dependent XRD as well as temperature-dependent IR studies reveal that cubic to tetragonal phase transition is lowered due to size effects. Observed changes in the IR spectra indicate that the paramagnetic–ferrimagnetic phase transition taking place at 74 K is related to further lowering of symmetry to orthorhombic system. Assignment of modes was proposed and factor group analyses in three possible symmetries were carried out. Our results show strong anomalies due to the Jahn–Teller tetragonal distortion and weak due to the orthorhombic distortion and onset of collinear ferrimagnetic order. Shifts of wavenumbers observed below 31 K, where the onset of antiferromagnetic ordering occurs, were attributed to spin–phonon interactions. - Graphical abstract: XRD pattern of NiCr{sub 2}O{sub 4} sample synthesized via a coprecipitation method followed by calcination at 1000 {sup o}C. - Highlights: • NiCr{sub 2}O{sub 4} starts to crystallize near 750 °C. • Coexistence of cubic and tetragonal phases of NiCr{sub 2}O{sub 4} was revealed. • Temperature of the Jahn–Teller distortion is lowered due to the size effects. • Evidences of tetragonal and orthorhombic distortions were found. •more » Weak spin–phonon interactions were evidenced.« less

Authors:
; ; ; ;
Publication Date:
OSTI Identifier:
22306296
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 201; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALLOCATIONS; ANTIFERROMAGNETISM; CALCINATION; COPRECIPITATION; INFRARED SPECTRA; INTERACTIONS; JAHN-TELLER EFFECT; MAGNETIZATION; ORTHORHOMBIC LATTICES; PARAMAGNETISM; PHASE TRANSFORMATIONS; PHONONS; POWDERS; SCANNING ELECTRON MICROSCOPY; SPIN; TEMPERATURE DEPENDENCE; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION

Citation Formats

Ptak, M., E-mail: m.ptak@int.pan.wroc.pl, Maczka, M., Gągor, A., Pikul, A., Macalik, L., and Hanuza, J. Temperature-dependent XRD, IR, magnetic, SEM and TEM studies of Jahn–Teller distorted NiCr{sub 2}O{sub 4} powders. United States: N. p., 2013. Web. doi:10.1016/J.JSSC.2013.03.023.
Ptak, M., E-mail: m.ptak@int.pan.wroc.pl, Maczka, M., Gągor, A., Pikul, A., Macalik, L., & Hanuza, J. Temperature-dependent XRD, IR, magnetic, SEM and TEM studies of Jahn–Teller distorted NiCr{sub 2}O{sub 4} powders. United States. doi:10.1016/J.JSSC.2013.03.023.
Ptak, M., E-mail: m.ptak@int.pan.wroc.pl, Maczka, M., Gągor, A., Pikul, A., Macalik, L., and Hanuza, J. Wed . "Temperature-dependent XRD, IR, magnetic, SEM and TEM studies of Jahn–Teller distorted NiCr{sub 2}O{sub 4} powders". United States. doi:10.1016/J.JSSC.2013.03.023.
@article{osti_22306296,
title = {Temperature-dependent XRD, IR, magnetic, SEM and TEM studies of Jahn–Teller distorted NiCr{sub 2}O{sub 4} powders},
author = {Ptak, M., E-mail: m.ptak@int.pan.wroc.pl and Maczka, M. and Gągor, A. and Pikul, A. and Macalik, L. and Hanuza, J.},
abstractNote = {In the present work we report detailed structural, magnetic and phonon properties of NiCr{sub 2}O{sub 4} powders synthesized via a simple coprecipitation method. Temperature-dependent XRD as well as temperature-dependent IR studies reveal that cubic to tetragonal phase transition is lowered due to size effects. Observed changes in the IR spectra indicate that the paramagnetic–ferrimagnetic phase transition taking place at 74 K is related to further lowering of symmetry to orthorhombic system. Assignment of modes was proposed and factor group analyses in three possible symmetries were carried out. Our results show strong anomalies due to the Jahn–Teller tetragonal distortion and weak due to the orthorhombic distortion and onset of collinear ferrimagnetic order. Shifts of wavenumbers observed below 31 K, where the onset of antiferromagnetic ordering occurs, were attributed to spin–phonon interactions. - Graphical abstract: XRD pattern of NiCr{sub 2}O{sub 4} sample synthesized via a coprecipitation method followed by calcination at 1000 {sup o}C. - Highlights: • NiCr{sub 2}O{sub 4} starts to crystallize near 750 °C. • Coexistence of cubic and tetragonal phases of NiCr{sub 2}O{sub 4} was revealed. • Temperature of the Jahn–Teller distortion is lowered due to the size effects. • Evidences of tetragonal and orthorhombic distortions were found. • Weak spin–phonon interactions were evidenced.},
doi = {10.1016/J.JSSC.2013.03.023},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = 201,
place = {United States},
year = {2013},
month = {5}
}