Submit to Materials Review for Materials Propose a Special Issue

Journal Browser

Advanced Electron Paramagnetic Resonance Spectroscopy for Structural Characterization

Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Advanced Materials Characterization".

Deadline for manuscript submissions: closed (20 June 2022) | Viewed by 4445

Share This Special Issue

Special Issue Editors

Prof. Dr. Slawomir Kaczmarek

E-Mail Website
Guest Editor

Department of Technical Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology, Al. Piastów 17, 70-310 Szczecin, Poland
Interests: laser diodes; scintillators; solid and nanoparticles materials characterization; EPR investigations, magnetic properties
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Tomasz Bodziony

E-Mail Website
Guest Editor

Department of Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology, Al. Piastów 17, 70-310 Szczecin, Poland
Interests: generally solid state physics; especially EPR (electron paramagnetic resonance) magnetic properties of solids and magnetic measurements (SQUID); optical; infrared and XRD spectroscopy; crystallography

Special Issue Information

Dear Colleagues,

The aim of this publication is to study the relationship between electron paramagnetic resonance theory and the structural properties of solids, e.g., crystals. The paramagnetic ion can be treated as an active dopant or a kind of probe doped to the host, e.g., crystal lattice. In both cases, the experimental EPR spectra and their analysis give some knowledge about the structural position of the ion and its surroundings, local symmetry, deformation, the displacement of a dopant ion with respect to a substituted ion, similar or dissimilar pair formation, etc. This is especially important for future applications of the investigated materials such as laser diodes, phosphors, and scintillators. Theoretical calculations, based on spin-Hamiltonian parameter findings, are less expensive as compared to, e.g., crystal growth, and can give unique information about the structure of the investigated material. To date, only a few dopants have been analyzed using the superposition model, perturbation methods, or Newman g-shift model with the aim of finding the local structure of the doped material or the local symmetry of the doped ion. Additionally, the applied methods are not the only ones that can be applied to theoretical calculations of spin-Hamiltonian parameters.

Prof. Dr. Slawomir Kaczmarek
Prof. Dr. Tomasz Bodziony
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

electron paramagnetic resonance
spin-Hamiltonian
active centers
local symmetry
theoretical calculations
superposition model
perturbation methods

Published Papers (3 papers)

Download All Papers

Research

12 pages, 1891 KiB

Open AccessArticle

Theoretical and Structural Study of Axial Symmetry Ce³⁺ Centers in the BaWO₄ Single Crystal Doped with Cerium and Codoped with Sodium Ions

by Tomasz Bodziony

Materials 2022, 15(16), 5749; https://doi.org/10.3390/ma15165749 - 20 Aug 2022

Viewed by 1121

Abstract

The spin–Hamiltonian parameters g–factors (

g_{| |}

and

g_{⊥}

) of the Ce³⁺ paramagnetic centers in BaWO₄: Ce and BaWO₄: Ce, Na single crystals with axial symmetry are investigated using the superposition model (SPM) via complete [...] Read more.

The spin–Hamiltonian parameters g–factors (

g_{| |}

and

g_{⊥}

) of the Ce³⁺ paramagnetic centers in BaWO₄: Ce and BaWO₄: Ce, Na single crystals with axial symmetry are investigated using the superposition model (SPM) via complete diagonalization procedure of energy matrix (CDM method). The calculated g–factors are in reasonable agreement with the experimental values. The fitted intrinsic parameters are comparable with data from other publications for rare-earth paramagnetic centers in a similar environment. The angular distortions of the cerium dodecahedron [CeO₈] are also studied. Structural analysis of paramagnetic centers with axial symmetry through the postulated cerium barium tetrahedron [CeBa₄] connected via oxygens bridges was carried out. The mechanism of the charge compensation and the role of the second dopant (Na⁺) is also discussed. Full article

(This article belongs to the Special Issue Advanced Electron Paramagnetic Resonance Spectroscopy for Structural Characterization)

► Show Figures

Figure 1

16 pages, 3944 KiB

Open AccessArticle

Radical Composition and Radical Reaction Kinetics in the Probe-Irradiated XLPE Samples as a Potential Source of Information on Their Aging Degree

by Hanna Lewandowska and Jarosław Sadło

Materials 2022, 15(16), 5723; https://doi.org/10.3390/ma15165723 - 19 Aug 2022

Viewed by 1396

Abstract

Polyethylene is a model polyolefin, and a widely used material for the manufacture of many products, including cable sheaths. Understanding degradation mechanisms at the atomic scale leading to oxidation during aging is crucial for many long-term applications. The concentrations of radicals derived from oxidation and chain scission during radio-oxidation, as well as their ratio, are important parameters controlling the predominance of chain scission or crosslinking of the polymer. In this work, we propose a cryogenic EPR technique for measuring oxidation- and fragmentation-derived radicals as a less-destructive method for the evaluation of cable insulation aging and performance capability. We investigate the effect of the low-dose and high-dose radiation aging on the formation of free radicals in the polymer matrix that are both unprotected and protected by antioxidants. The stability of radicals after aging is a determinant of macroscopic processes and structural changes during aging. Under the conditions of the higher dose rate, the peroxy radical buildup is lower per dose. Peroxy radical buildup is followed by decay during aging, in accordance with POOH content. Our results allow the prediction of the capability of the antioxidant to protect the XLPE material in the function of dose and time. Full article

(This article belongs to the Special Issue Advanced Electron Paramagnetic Resonance Spectroscopy for Structural Characterization)

► Show Figures

Figure 1

14 pages, 6641 KiB

Open AccessArticle

Applying the FMR Technique to Analyzing the Influence of Nitriding on the Magnetic Properties of Steel

by Slawomir Maksymilian Kaczmarek, Jerzy Michalski, Grzegorz Leniec, Hubert Fuks, Tadeusz Frączek and Agata Dudek

Materials 2022, 15(12), 4080; https://doi.org/10.3390/ma15124080 - 8 Jun 2022

Cited by 2 | Viewed by 1312

Abstract

This paper presents the relationship between the chemical composition and size of steel balls, the parameters of the nitriding process, and their magnetic properties, defined in this study by ferromagnetic resonance (FMR) and SQUID. Balls made from AISI 1010 and AISI 52100 steels, with diameters of 2.5 and 3 mm, respectively, were investigated. On samples made of AISI 1010 and AISI 52100 steel, single-phase layers of iron nitrides γ’ with a thickness of g_mp = 50 and 37 μm, respectively, were produced. Then, the samples were annealed at a temperature of 520 °C for 4 h in an inert atmosphere (N₂/Ar) at a pressure of 200 Pa. After the nitriding processes, steel balls were subjected to standard physical metallurgy and X-ray examinations. During annealing of nitrided layers with a two-phase layer of iron nitrides, at first, the transformation of the ε phase into the γ’ phase with the release of nitrogen into the atmosphere takes place. The FMR signals did not originate from isolated ions, but from more magnetically complex systems, e.g., Fe–Fe pairs or iron clusters, while the observed FMR line position is normally even lower and occurs for a magnetic induction below 200 mT. The fact that the magnetic centers did not contain mainly isolated Fe ions, additionally confirmed the abnormal increase in resonance signal intensity as a function of temperature, which is a behavior inconsistent with the Curie–Weiss law. The results obtained from measurements by the SQUID method, recording variations in magnetization as a function of temperature, confirm the untypical reinforcement of the magnetic conditions of the samples with the increase in temperature. For the samples tested, the magnetization was relatively weaker when the tests were conducted in a stronger magnetic field. Full article

(This article belongs to the Special Issue Advanced Electron Paramagnetic Resonance Spectroscopy for Structural Characterization)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Advanced Electron Paramagnetic Resonance Spectroscopy for Structural Characterization

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (3 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI