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Nanomaterials
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Oxide Magnetics
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Oxide Magnetics

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Synthesis, Interfaces and Nanostructures".

Deadline for manuscript submissions: closed (31 July 2021) | Viewed by 19133

Special Issue Editor

Prof. Dr. Sergei Trukhanov

E-Mail Website
Guest Editor
Scientific Practical Materials Research Centre of National Academy of Sciences of Belarus, Minsk, Belarus
Interests: chemistry and physics of complex transition metal alloys and oxides in micro-, meso-, and nanoforms; crystal and magnetic structures; phase transitions; magnetic state; colossal magnetoresistance; magnetoelectric effect; multiferroics; microwave absorption; microwave magnetodielectric materials for 5G technology; functional composite materials for microwave absorption
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear colleagues,

Preparation of complex transition metal oxides and investigation of their structure, magnetic, electrical, and dielectric properties is an actual trend of condensed matter physics and chemistry. This topic is not only important from a fundamental point of view, but it also has great applied importance. Complex transition metal oxides belong to the so-called class of strongly correlated electronic systems, since they demonstrate a strong interconnection of magnetic, electrical, and elastic properties among the most commonly used 3D metals, such as Cr, Mn, Fe, Co, and Ni. However, the most promising for practical use are iron-based oxides with perovskite (orthoferrites), spinel (spinel-ferrites), and magnetoplumbite (hexaferrites) structures. Their prospects are determined by high values of total magnetic moment and temperature of phase transitions. Nanometer particle size significantly alters their electronic properties. Complex transition metal oxides are promising for practical use as permanent magnets, spintronics elements, and microwave materials for 5G communication technology.

Prof. Dr. Sergei Trukhanov
Guest Editor

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Keywords

  • crystal structure
  • magnetic structure
  • magnetization
  • magnetic phase transition
  • electrical resistivity
  • magnetoresistance
  • polarization
  • magnetodielectric
  • multiferroics
  • microwave absorption

Published Papers (5 papers)

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Research

19 pages, 3877 KiB  
Article
Structural, Magnetic, and AC Measurements of Nanoferrites/Graphene Composites
by Shaimaa A. Habib, Samia A. Saafan, Talaat M. Meaz, Moustafa A. Darwish, Di Zhou, Mayeen U. Khandaker, Mohammad A. Islam, Hamidreza Mohafez, Alex V. Trukhanov, Sergei V. Trukhanov and Maha K. Omar
Nanomaterials 2022, 12(6), 931; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12060931 - 11 Mar 2022
Cited by 38 | Viewed by 3490
Abstract
As a contribution to the graphene-based nanoferrite composites, this article is intended to present Mn, Co, and Co-Mn nanoferrites for the preparation and investigation of such samples. Nanoparticles of Co ferrite, Mn ferrite, and Co-Mn ferrite were chemically synthesized by the coprecipitation method. [...] Read more.
As a contribution to the graphene-based nanoferrite composites, this article is intended to present Mn, Co, and Co-Mn nanoferrites for the preparation and investigation of such samples. Nanoparticles of Co ferrite, Mn ferrite, and Co-Mn ferrite were chemically synthesized by the coprecipitation method. The composites of ferrite/graphene were made by incorporating weight ratios of 25% graphene to 75% ferrite. Various structural and characterizing investigations of ferrite samples and ferrite/graphene composites were performed, including XRD, EDX, SEM, VSM hysteresis loops, AC conductivity, and dielectric behavior. The investigations ensured the formation of the intended nanoferrite powders, each having a single-phase crystal structure with no undesired phases or elements. All samples exhibit a soft magnetic behavior. They show a semiconducting behavior of AC electrical conductivity as well. This was proved by the temperature dependence of the AC’s electrical conductivity. Whereas the dielectric function and loss tangent show an expected, well-explained behavior, the ferrite/graphene composite samples have lower saturation magnetization values, lower AC conductivity, and dielectric constant values than the pure ferrites but still have the same behavior trends as those of the pure ferrites. The values obtained may represent steps on developing new materials for expected applications, such as manufacturing supercapacitors and/or improved battery electrodes. Full article
(This article belongs to the Special Issue Oxide Magnetics)
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17 pages, 7891 KiB  
Article
Structural and Magnetic Properties of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4/ZnFe2O4 Spinel Ferrite Nanocomposites: Comparative Study between Sol-Gel and Pulsed Laser Ablation in Liquid Approaches
by Munirah A. Almessiere, Sadik Güner, Yassine Slimani, Mohammed Hassan, Abdulhadi Baykal, Mohammed Ashraf Gondal, Umair Baig, Sergei V. Trukhanov and Alex V. Trukhanov
Nanomaterials 2021, 11(9), 2461; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11092461 - 21 Sep 2021
Cited by 61 | Viewed by 3053
Abstract
In this study, the samples of the ZnFe2O4 (ZFO) spinel ferrites nanoparticles (SFNPs), Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 (CNGaGdFO) SFNPs and (Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 [...] Read more.
In this study, the samples of the ZnFe2O4 (ZFO) spinel ferrites nanoparticles (SFNPs), Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 (CNGaGdFO) SFNPs and (Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4)x/(ZnFe2O4)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) (CNGaGdFO)x/(ZFO)y spinel ferrite nanocomposites (NC) have been synthesized by both sol-gel and Green pulsed laser ablation in liquid (PLAL) approaches. All products were characterized by X-ray powder diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), elemental mappings and energy dispersive X-ray spectroscopy (EDX). It was objected to tune the magnetic properties of a soft spinel ferrite material with a softer one by mixing them with different fractions. Some key findings are as follows. M-H investigations revealed the exhibition of ferrimagnetic phases for all synthesized samples (except ZnFe2O4) that were synthesized by sol-gel or PLAL methods at both 300 K and 10 K. ZnFe2O4 ferrite NPs exhibits almost paramagnetic feature at 300 K and glass-like phase at very low temperatures below 19.23 K. At RT analyses, maximum saturation magnetization (MS) of 66.53 emu/g belongs to nanocomposite samples that was synthesized by sol-gel method and x:y ratio of 1:3. At 10 K analyses, MS,max = 118.71 emu/g belongs to same nanocomposite samples with ratio of 1:3. Maximum coercivities are 625 Oe belonging to CNGaGdFO and 3564 Oe belonging to NC sample that was obtained by sol-gel route having the 3:1 ratio. Squareness ratio (SQRs = Mr/MS) of NC sample (sol-gel, 4:1 ratio) is 0.371 as maximum and other samples have much lower values until a minimum of 0.121 (laser, 3:1) assign the multi-domain wall structure for all samples at 300 K. At 10 K data, just CNGaGdFO has 0.495 SQR value assigning single domain nature. The maximum values of effective crystal anisotropy constant (Keff) are 5.92 × 104 Erg/g and 2.4 × 105 Erg/g belonging to CNGaGdFO at 300 K and 10 K, respectively. Further, this sample has an internal anisotropy field Ha of 1953 Oe as largest at 300 K. At 10 K another sample (sol-gel, 3:1 ratio) has Ha,max of 11138 Oe which can also be classified as a soft magnetic material similar to other samples. Briefly, most magnetic parameters of NCs that were synthesized by sol-gel route are stronger than magnetic parameters of the NCs that were synthesized by PLAL at both temperatures. Some NC samples were observed to have stronger magnetic data as compared to magnetic parameters of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 NPs at 10 K. Full article
(This article belongs to the Special Issue Oxide Magnetics)
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13 pages, 2941 KiB  
Article
Understanding the Dependence of Nanoparticles Magnetothermal Properties on Their Size for Hyperthermia Applications: A Case Study for La-Sr Manganites
by Mylla C. Ferreira, Bruno Pimentel, Vivian Andrade, Vladimir Zverev, Radel R. Gimaev, Andrei S. Pomorov, Alexander Pyatakov, Yulia Alekhina, Aleksei Komlev, Liudmila Makarova, Nikolai Perov and Mario S. Reis
Nanomaterials 2021, 11(7), 1826; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11071826 - 14 Jul 2021
Cited by 21 | Viewed by 2369
Abstract
Magnetic oxides are promising materials for alternative health diagnoses and treatments. The aim of this work is to understand the dependence of the heating power with the nanoparticle (NP) mean size, for the manganite composition La0.75Sr0.25MnO3 (LSMO)—the one [...] Read more.
Magnetic oxides are promising materials for alternative health diagnoses and treatments. The aim of this work is to understand the dependence of the heating power with the nanoparticle (NP) mean size, for the manganite composition La0.75Sr0.25MnO3 (LSMO)—the one with maximum critical temperature for the whole La/Sr ratio of the series. We have prepared four different samples, each one annealed at different temperatures, in order to produce different mean NP sizes, ranging from 26 nm up to 106 nm. Magnetization measurements revealed a FC-ZFC irreversibility and from the coercive field as function of temperature we determined the blocking temperature. A phase diagram was delivered as a function of the NP mean size and, based on this, the heating mechanism understood. Small NPs (26 nm) is heated up within the paramagnetic range of temperature (T>Tc), and therefore provide low heating efficiency; while bigger NPs are heated up, from room temperature, within the magnetically blocked range of temperature (T<TB), and also provide a small heating efficiency. The main finding of this article is related with the heating process for NPs within the magnetically unblocked range of temperature (Tc>T>TB), for intermediate mean diameter size of 37 nm, with maximum efficiency of heat transfer. Full article
(This article belongs to the Special Issue Oxide Magnetics)
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12 pages, 2907 KiB  
Article
Peculiarities of the Crystal Structure Evolution of BiFeO3–BaTiO3 Ceramics across Structural Phase Transitions
by Dmitry V. Karpinsky, Maxim V. Silibin, Sergei V. Trukhanov, Alex V. Trukhanov, Alexander L. Zhaludkevich, Siarhei I. Latushka, Dmitry V. Zhaludkevich, Vladimir A. Khomchenko, Denis O. Alikin, Alexander S. Abramov, Tomasz Maniecki, Waldemar Maniukiewicz, Martin Wolff, Volker Heitmann and Andrei L. Kholkin
Nanomaterials 2020, 10(4), 801; https://0-doi-org.brum.beds.ac.uk/10.3390/nano10040801 - 21 Apr 2020
Cited by 62 | Viewed by 4075
Abstract
Evolution of the crystal structure of ceramics BiFeO3–BaTiO3 across the morphotropic phase boundary was analyzed using the results of macroscopic measuring techniques such as X-ray diffraction, differential scanning calorimetry, and differential thermal analysis, as well as the data obtained by [...] Read more.
Evolution of the crystal structure of ceramics BiFeO3–BaTiO3 across the morphotropic phase boundary was analyzed using the results of macroscopic measuring techniques such as X-ray diffraction, differential scanning calorimetry, and differential thermal analysis, as well as the data obtained by local scale methods of scanning probe microscopy. The obtained results allowed to specify the concentration and temperature regions of the single phase and phase coexistent regions as well as to clarify a modification of the structural parameters across the rhombohedral–cubic phase boundary. The structural data show unexpected strengthening of structural distortion specific for the rhombohedral phase, which occurs upon dopant concentration and temperature-driven phase transitions to the cubic phase. The obtained results point to the non-monotonous character of the phase evolution, which is specific for metastable phases. The compounds with metastable structural state are characterized by enhanced sensitivity to external stimuli, which significantly expands the perspectives of their particular use. Full article
(This article belongs to the Special Issue Oxide Magnetics)
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16 pages, 2004 KiB  
Article
Investigation of AC-Measurements of Epoxy/Ferrite Composites
by Moustafa A. Darwish, Alex V. Trukhanov, Oleg S. Senatov, Alexander T. Morchenko, Samia A. Saafan, Ksenia A. Astapovich, Sergei V. Trukhanov, Ekaterina L. Trukhanova, Andrey A. Pilyushkin, Antonio Sergio B. Sombra, Di Zhou, Rajshree B. Jotania and Charanjeet Singh
Nanomaterials 2020, 10(3), 492; https://0-doi-org.brum.beds.ac.uk/10.3390/nano10030492 - 09 Mar 2020
Cited by 125 | Viewed by 5184
Abstract
A pure ferrite and epoxy samples as well as the epoxy/ferrite composites with different 20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.% weight ferrite contents have been prepared by the chemical co-precipitation method. AC-conductivity and dielectric properties such as the dielectric constant [...] Read more.
A pure ferrite and epoxy samples as well as the epoxy/ferrite composites with different 20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.% weight ferrite contents have been prepared by the chemical co-precipitation method. AC-conductivity and dielectric properties such as the dielectric constant and dielectric loss of the prepared samples have been studied. The obtained results showed that the samples had a semiconductor behavior. The dielectric constant of the composites has been calculated theoretically using several models. For the composite sample that contains 20 wt.% of ferrites, these models give satisfactory compliance, while for the composite samples with a higher percentage of nanofillers, more than 30 wt.% theoretical results do not coincide with experimental data. The investigated polymer has very low conductivity, so this type of polymer can be useful for high-frequency applications, which can reduce the losses caused by eddy current. Thus, the prepared samples are promising materials for practical use as elements of microwave devices. Full article
(This article belongs to the Special Issue Oxide Magnetics)
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