Room temperature ferromagnetism in pure and ion-doped SnO2 nanoparticles

2017 ◽  
Vol 31 (36) ◽  
pp. 1750351 ◽  
Author(s):  
A. T. Apostolov ◽  
I. N. Apostolova ◽  
S. Trimper ◽  
J. M. Wesselinowa
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Sno2 Nanoparticles ◽  
Room Temperature Ferromagnetism ◽  
Surface Oxygen ◽  
Local Distribution ◽  
Strong Connection ◽  
Co Doping ◽  
Co Concentration ◽  
Good Agreement

Using a microscopic model taking into account the spin–phonon interactions we have studied the magnetic properties of pure and ion-doped SnO2 nanoparticles (NPs). The magnetization M in pure SnO2 NPs is due to surface oxygen vacancies. By doping with magnetic Co ion we observe a maximum in M for small Co-concentration, x = 1%, whereas for nonmagnetic Cu ion M increases with x. By Co-doping there is a local distribution for small Co-concentration, whereas by Cu this is not the case. It is shown that there is a strong connection between the lattice and M. The results are in good agreement with the experimental data.

scholarly journals Influence of oxygen vacancies on magnetic and transport properties of thin Zn1-xCoxOy films

2018 ◽  
Vol 185 ◽  
pp. 06013
Author(s):  
Andrey A. Lotin ◽  
Alina S. Kuz’mina ◽  
Oleg A. Novodvorsky ◽  
Liubov S. Parshina ◽  
Olga D. Khramova ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Impurity Concentration ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Deposition Method ◽  
Sapphire Substrates ◽  
Doping Impurity ◽  
Co Concentration

The features of the structural, transport and magnetic properties of thin Zn1-xCoxOy films (x=0-0.45), fabricated on С-sapphire substrates by the pulsed laser deposition method are studied. It is found that the transport and ferromagnetic properties of the wurtzite Zn1-xCoxOy films nonmonotonously depend on Co concentration at room temperature. For the Zn0.87Co0.13Oy film, the strongest ferromagnetic signal is observed that is caused by formation of the greatest number of metallic Co clusters. A further increase of doping impurity concentration in the films leads to the oxidation of metallic Co and formation of the paramagnetic Co3O4 phase, in consequence of which the ferromagnetic signal subsides.

scholarly journals Studies on Structural and Morphological Properties of Multidoped Ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ(x=0.2) as Solid Solutions

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Marija Stojmenović ◽  
Maja C. Pagnacco ◽  
Vladimir Dodevski ◽  
Jelena Gulicovski ◽  
Milan Žunić ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Solid Solutions ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Fluorite Structure ◽  
Lattice Parameter ◽  
Morphological Properties ◽  
Fluorite Type ◽  
Potential Improvement

The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ(x=0.2) with the fluorite type crystal structure of CeO2were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method) and room temperature self-propagating reaction (SPRT method). All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4+ions were replaced with cations (dopants) of lower valence state (3+), which may indicate the potential improvement of ionic conductivity. Additionally, the presence of oxygen vacancies in the lattice ceria, as well as very developed grain boundaries, gives a new possibility for potential application of obtained nanopowders in the area of room temperature ferromagnetism as spintronics.

Enhanced room temperature ferromagnetism in Cr and Fe co-doped SnO2 nanoparticles synthesized by sol-gel method

Vacuum ◽  
2020 ◽  
Vol 181 ◽  
pp. 109635 ◽  
Author(s):  
Monika Duhan ◽  
Naveen Kumar ◽  
Anita Gupta ◽  
Anupinder Singh ◽  
Harminder Kaur
Keyword(s):  
Room Temperature ◽  
Sno2 Nanoparticles ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Co Doped

Significant room-temperature ferromagnetism in porous ZnO films: The role of oxygen vacancies

2015 ◽  
Vol 200 ◽  
pp. 22-27 ◽  
Author(s):  
Xue Hou ◽  
Huiyuan Liu ◽  
Huiyuan Sun ◽  
Lihu Liu ◽  
Xiaoxuan Jia
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Zno Films

scholarly journals Morphological and Optical Properties of Cobalt Ion-Modified ZnO Nanowires

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 614
Author(s):  
Seok Cheol Choi ◽  
Do Kyung Lee ◽  
Sang Ho Sohn
Keyword(s):  
Optical Properties ◽  
Hydrothermal Synthesis ◽  
Oxygen Vacancies ◽  
Morphological Changes ◽  
Zno Nanowires ◽  
Oxide Cluster ◽  
Co Doping ◽  
Co Concentration ◽  
Acetate Hydrate ◽  
Low Levels

In this study, we prepared cobalt (Co) ion-modified ZnO nanowires using hydrothermal synthesis with zinc acetate dehydrate and Co (II) acetate hydrate precursors in ethanol solutions. Their morphological and optical properties were investigated with varying Co precursor concentration. The morphological changes of the ZnO nanowires depended positively on the concentration of the Co precursor. The ZnO nanowires showed modified crystal orientations and nanostructure shapes depending on the Co concentration in the solutions. Variations in the optical properties of the Co ion-modified ZnO nanowires could be explained by the interaction of the Co ions with the band electrons, oxygen vacancies, and zinc interstitials. The overall growth and characteristics of ZnO nanowires synthesized in solutions containing low levels of Co ions were related to Co doping into the ZnO bulks. In solutions containing high levels of Co ions, these were additionally related to the Co oxide cluster.

Surface oxygen vacancies on Co3O4 mediated catalytic formaldehyde oxidation at room temperature

2016 ◽  
Vol 6 (11) ◽  
pp. 3845-3853 ◽  
Author(s):  
Zhong Wang ◽  
Wenzhong Wang ◽  
Ling Zhang ◽  
Dong Jiang
Keyword(s):  
Catalytic Oxidation ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Essential Role ◽  
Surface Oxygen ◽  
Oxidation Reactions ◽  
Major Activity ◽  
Formaldehyde Oxidation ◽  
The Common

This study reveals the essential role played by surface oxygen vacancies in catalytic oxidation reactions, and complements the common viewpoint that Co3+ is the major activity species in Co3O4-based systems.

Room-Temperature Ferromagnetism in Co-Doped SrTiO3 Nanofibres

2012 ◽  
Vol 512-515 ◽  
pp. 1438-1441
Author(s):  
Wei Zhang ◽  
He Ping Li ◽  
Wei Pan
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Magnetic Ordering ◽  
Second Phase ◽  
Co Doped

In this article, Co-doped SrTiO3 nanofibres have been prepared by electrospinning from a sol-gel precursor and the following calcination at 923K. XRD results confirmed that no second phase was formed, and Co ions successfully occupied the Ti sites. By annealing in hydrogen, oxygen vacancies and (Co-H-Co) were formed, which both contributed to the magnetic ordering in SrTi1-xCoxO3 nanofibres are at 300K.

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