Dielectrics

Paramagnetic centers of uncontrolled impurities in ZnWO$_4$ doped with rare earths and lithium

V. A. Vazhenin^a, M. Yu. Artemov^a, A. P. Potapov^a, K. A. Subbotin^bc, A. V. Fokin^a, Yu. I. Zimina^bc, A. I. Titov^b, D. A. Lis<sup>b

a</sup> Institute of Natural Sciences and Mathematics, Ural Federal University
^b Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow
^c D. Mendeleev University of Chemical Technology of Russia

Abstract: Single crystals of ZnWO$_4$ grown by the Czochralski method and doped with Yb or Tm, as well as Li, were studied by the EPR method. Transitions of monoclinic centers of Fe$^{3+}$, Cr$^{3+}$ and Gd$^{3+}$ were observed, similar to the previously studied spectra in lithium-free crystals. Spectra of triclinic centers detected in samples free of lithium admixture and attributed to dimers (paramagnetic ion – zinc vacancy) were not observed. However, new satellites appeared, accompanying the transitions of monoclinic centers in a wide range of magnetic field orientations. It is reasonable to assume that these centers (triclinic and monoclinic) arise as a result of association of paramagnetic ions with lithium ions in zinc positions. Measurement of the orientational behavior of intradoublet (in the case of Gd$^{3+}$ and interdoublet) transitions in two orthogonal planes made it possible to determine the parameters of their spin Hamiltonians.

Keywords: zinc tungstate, impurity ions, iron group, REE, paramagnetic resonance.

Received: 28.06.2025
Revised: 28.07.2025
Accepted: 08.08.2025

DOI: 10.61011/FTT.2025.09.61617.216-25

Bibliographic databases:

•