Temperature study of magnetic resonance spectra of co-modified (Co,N)-TiO2 nanocomposites

Nikos Guskos; Janusz Typek; Grzegorz Zolnierkiewicz; Aleksander Guskos; Pawel Berczynski; Diana Dolat; Sylwia Mozia; Konstantinos Aidinis; Konrad Kruk; Antoni W. Morawski

doi:10.1515/msp-2016-0042

Temperature study of magnetic resonance spectra of co-modified (Co,N)-TiO₂ nanocomposites

Nikos Guskos
, Janusz Typek
, Grzegorz Zolnierkiewicz
, Aleksander Guskos
, Pawel Berczynski
, Diana Dolat
, Sylwia Mozia
, Konstantinos Aidinis
, Konrad Kruk
, Antoni W. Morawski

National and Kapodistrian University of Athens
West Pomeranian University of Technology

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

4 Scopus citations

Abstract

The (nCo,N)-TiO₂ (n = 1, 5 and 10 wt.% of Co) nanocomposites were investigated by magnetic resonance spectroscopy in 4 K to 290 K range. Analyses of ferromagnetic/electron paramagnetic resonance (FMR/EPR) spectra in terms of four Callen lineshape components revealed the existence of two types of magnetic centers, one derived from metallic cobalt nanoparticles in superparamagnetic (SPM) phase and the other from cobalt clusters in the TiO₂ lattice. Additionally, at low temperature the EPR spectrum arising from Ti³⁺ ions was also registered. Both relaxations of the Landau-Lifshitz type and the Bloch-Bloembergen type played an important role at high temperature in determining the linewidths and the latter relaxation was prevailing at low temperature. Analysis of the integrated intensity showed that the SPM signal is due to small size FM cobalt nanoparticles while the paramagnetic signal from Co clusters originates from those nanoparticles in which the concentration of magnetic polarons is below the percolation threshold.

Original language	English
Pages (from-to)	242-250
Number of pages	9
Journal	Materials Science-Poland
Volume	34
Issue number	2
DOIs	https://doi.org/10.1515/msp-2016-0042
State	Published - 1 Jun 2016
Externally published	Yes

Keywords

Nano titanium dioxide
electron paramagnetic resonance
photocatalyst

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@article{d1420ce19f014fcb83fb1c97ee86ff48,

title = "Temperature study of magnetic resonance spectra of co-modified (Co,N)-TiO2 nanocomposites",

abstract = "The (nCo,N)-TiO2 (n = 1, 5 and 10 wt.\% of Co) nanocomposites were investigated by magnetic resonance spectroscopy in 4 K to 290 K range. Analyses of ferromagnetic/electron paramagnetic resonance (FMR/EPR) spectra in terms of four Callen lineshape components revealed the existence of two types of magnetic centers, one derived from metallic cobalt nanoparticles in superparamagnetic (SPM) phase and the other from cobalt clusters in the TiO2 lattice. Additionally, at low temperature the EPR spectrum arising from Ti3+ ions was also registered. Both relaxations of the Landau-Lifshitz type and the Bloch-Bloembergen type played an important role at high temperature in determining the linewidths and the latter relaxation was prevailing at low temperature. Analysis of the integrated intensity showed that the SPM signal is due to small size FM cobalt nanoparticles while the paramagnetic signal from Co clusters originates from those nanoparticles in which the concentration of magnetic polarons is below the percolation threshold.",

keywords = "Nano titanium dioxide, electron paramagnetic resonance, photocatalyst",

author = "Nikos Guskos and Janusz Typek and Grzegorz Zolnierkiewicz and Aleksander Guskos and Pawel Berczynski and Diana Dolat and Sylwia Mozia and Konstantinos Aidinis and Konrad Kruk and Morawski, \{Antoni W.\}",

note = "Publisher Copyright: {\textcopyright} 2016 Wroclaw University of Technology.",

year = "2016",

month = jun,

day = "1",

doi = "10.1515/msp-2016-0042",

language = "English",

volume = "34",

pages = "242--250",

journal = "Materials Science-Poland",

issn = "2083-1331",

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TY - JOUR

T1 - Temperature study of magnetic resonance spectra of co-modified (Co,N)-TiO2 nanocomposites

AU - Guskos, Nikos

AU - Typek, Janusz

AU - Zolnierkiewicz, Grzegorz

AU - Guskos, Aleksander

AU - Berczynski, Pawel

AU - Dolat, Diana

AU - Mozia, Sylwia

AU - Aidinis, Konstantinos

AU - Kruk, Konrad

AU - Morawski, Antoni W.

PY - 2016/6/1

Y1 - 2016/6/1

N2 - The (nCo,N)-TiO2 (n = 1, 5 and 10 wt.% of Co) nanocomposites were investigated by magnetic resonance spectroscopy in 4 K to 290 K range. Analyses of ferromagnetic/electron paramagnetic resonance (FMR/EPR) spectra in terms of four Callen lineshape components revealed the existence of two types of magnetic centers, one derived from metallic cobalt nanoparticles in superparamagnetic (SPM) phase and the other from cobalt clusters in the TiO2 lattice. Additionally, at low temperature the EPR spectrum arising from Ti3+ ions was also registered. Both relaxations of the Landau-Lifshitz type and the Bloch-Bloembergen type played an important role at high temperature in determining the linewidths and the latter relaxation was prevailing at low temperature. Analysis of the integrated intensity showed that the SPM signal is due to small size FM cobalt nanoparticles while the paramagnetic signal from Co clusters originates from those nanoparticles in which the concentration of magnetic polarons is below the percolation threshold.

AB - The (nCo,N)-TiO2 (n = 1, 5 and 10 wt.% of Co) nanocomposites were investigated by magnetic resonance spectroscopy in 4 K to 290 K range. Analyses of ferromagnetic/electron paramagnetic resonance (FMR/EPR) spectra in terms of four Callen lineshape components revealed the existence of two types of magnetic centers, one derived from metallic cobalt nanoparticles in superparamagnetic (SPM) phase and the other from cobalt clusters in the TiO2 lattice. Additionally, at low temperature the EPR spectrum arising from Ti3+ ions was also registered. Both relaxations of the Landau-Lifshitz type and the Bloch-Bloembergen type played an important role at high temperature in determining the linewidths and the latter relaxation was prevailing at low temperature. Analysis of the integrated intensity showed that the SPM signal is due to small size FM cobalt nanoparticles while the paramagnetic signal from Co clusters originates from those nanoparticles in which the concentration of magnetic polarons is below the percolation threshold.

KW - Nano titanium dioxide

KW - electron paramagnetic resonance

KW - photocatalyst

UR - https://www.scopus.com/pages/publications/84978919873

U2 - 10.1515/msp-2016-0042

DO - 10.1515/msp-2016-0042

M3 - Article

AN - SCOPUS:84978919873

SN - 2083-1331

VL - 34

SP - 242

EP - 250

JO - Materials Science-Poland

JF - Materials Science-Poland

IS - 2

ER -

Temperature study of magnetic resonance spectra of co-modified (Co,N)-TiO₂ nanocomposites

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Keywords

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