0000000000082225
AUTHOR
A Fedotovs
showing 7 related works from this author
EPR studies of the oxyfluoride glass ceramics using Mn2+as a paramagnetic probe
2010
In this work, we used Mn2+ as a dopant in the oxyfluoride glasses with various fluoride compounds. Electron paramagnetic resonance (EPR) measurements were carried out before and after a heat treatment of the material. In both cases, a well pronounced hyperfine (hf) structure of the EPR spectra characteristic to the Mn2+ ion have been observed. EPR measurements have also been studied for the separate fluoride counterparts of the oxyfluoride glasses. EPR spectra of the LaF3:Mn2+ and CaF2:Mn2+ powders show that Mn2+ ion has a strong superhyperfine (shf) interaction with surrounding fluorine nuclei, and this shf structure could be observed also in the heat treated glass samples.
Analysis of Mn2+EPR spectral shapes for studies of the oxyfluoride glass ceramics
2011
We investigated the EPR superhyperfine structure of the Mn 2+ ion in the disordered BaF2 crystalline media which tends to crystallize in the oxyfluoride glass-ceramics material. Obtained EPR spectra reveal explicit shf structure due to Mn 2+ ion building into the BaF2 lattice showing its usefulness as a probe in orientationally disordered and amorphous structures. Two types with explicit shf structure of Mn 2+ ion characteristic EPR spectra were obtained in BaF2 powder samples characteristic with broad (type 1) and narrow (type 2) hyperfine structure lines. Spectra of the ZnF2-BaF2 oxyfluoride glass-ceramics samples revealed explicit fine structure lines.
Oxidation State and Local Structure of Chromium Ions in LaOCl
2021
This research is funded by the Latvian Council of Science, project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1-0335. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017- TeamingPhase2 under grant agreement No. 739508, project CAMART2.
EPR Study of Gd3+local structure in ScF3crystal with negative thermal expansion coefficient
2015
Zero field splitting (ZFS) of Gd3+ impurity in ScF3 is studied by electron paramagnetic resonance at 77 and 295 K. ZFS parameter b4 values obtained from angular dependence simulations show that regardless of negative thermal expansion in ScF3 temperature dependence of |b4| is similar to other cubic fluoroperovskites. Our analysis of ZFS parameters indicates that the local structure of Gd3+ centres expands positively with temperature.
Electron paramagnetic resonance and magnetic circular dichroism of Gd3+ ions in oxyfluoride glass–ceramics containing CaF2 nanocrystals
2015
Abstract Magnetic resonance investigations of the Gd3 + centre structure in the oxyfluoride glass and glass–ceramics (GCs) have been carried out. The electron paramagnetic resonance (EPR) measurements showed the presence of low symmetry Gd3 + centres in the glass sample. The cubic Gd3 + centre appeared in the glass–ceramics after heat treatment of the samples at temperatures above 650 °C. The magnetic circular dichroism (MCD) measurements of both glass and glass–ceramics showed wide absorption band around 310 nm. In the GC samples MCD–EPR of the cubic Gd3 + centre has been detected.
Recombination luminescence of X-ray induced paramagnetic defects in BaY2F8
2020
This research is funded by the Latvian Council of Science , project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1–0335 . The crystal growth research was funded by the CNPq (Brazil), project NO 421581/2016–6 .
Crystalline phase detection in glass ceramics by EPR spectroscopy
2018
The advances of EPR spectroscopy for the detection of activators as well as determining their local structure in the crystalline phase of glass ceramics is considered. The feasibility of d-element (Mn2+, Cu2+) and f-element (Gd3+, Eu2+) ion probes for the investigation of glass ceramics is discussed. In the case of Mn2+, the information is obtained from the EPR spectrum superhyperfine structure, for Gd3+ and Eu2+ probes – from the EPR spectrum fine structure, whereas for Cu2+ ions the changes in the EPR spectrum shape could be useful. The examples of EPR spectra of the above-mentioned probes in oxyfluoride glass ceramics are illustrated. ----/ / /---- This is the preprint version of the fol…