mriselMagnetic Resonance in SolidsMagnetic Resonance in Solids2072-5981Kazan Federal University10.26907/mrsej-19502mrisel-79Research ArticleСтатьиA variable temperature EPR study of Cu2+ doped single crystals of pyrovanadates β-Mg2V2O7, α-Zn2V2O7: estimations of non-coincident g2- and A2-tensorsMisraS. K.

Montreal, QC, H3G 1M8

sushil.misra@concordia.caAndronenkoS. I.

Kremlevskaya 18, Kazan 420008

SIAndronenko@kpfu.ruPhysics Department, Concordia UniversityCanadaInstitute of Physics, Kazan Federal UniversityRussian Federation20193107201921519502 (11 pp.)Copyright © Misra S.K., Andronenko S.I., 20242024Misra S.K., Andronenko S.I.Misra S.K., Andronenko S.I.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://www.mrsej.ru/jour/article/view/79

Full angular variations of Cu2+ EPR spectra in β-Mg2V2O7 (MgVO) and α-Zn2V2O7 (ZnVO) were recorded for orientations of external magnetic field in three mutually perpendicular planes at 120 K and 295 K, as well as in temperature range from 110 to 295 K at some chosen orientations of magnetic field. The principal values of the g2- and A2-tensors, as well as the orientations of their principal axes were determined from angular variations of EPR line positions in three mutually perpendicular planes, using a rigorous least square fitting procedure, especially adapted to the case of non-coincident principal axes of the A2-tensors for the monoclinic and triclinic point-group symmetries in MgVO and ZnVO crystals, respectively. This procedure uses the eigenvalues and eigenvectors of the spin-Hamiltonian matrix, which allows to determine the orientations of the principal axes of the g2 (Zeeman) and A2 (hyperfine-interaction)-tensors. It is found, that the principal values of g2- and A2-tensors of the Cu2+ ions are similar in the two crystals; however, the orientations of the principal axes of these tensors are significantly different from each other. This is because the Cu2+ ion in MgVO is 6-fold coordinated, whereas it is 5-fold coordinated in trigonal bipyramidal coordination in ZnVO. The principal values of the g2-tensor, so obtained, are exploited to determine the electronic ground state of the Cu2+ ion in these two crystals.

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The authors declare that there are no conflicts of interest present.