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Prokhorov A.A.,A A Galkin Donetsk Physico Technical Institute | Prokhorov A.A.,ASCR Institute of Physics Prague | Prokhorov A.D.,A A Galkin Donetsk Physico Technical Institute | Chernush L.F.,A A Galkin Donetsk Physico Technical Institute | And 4 more authors.
Physica Scripta | Year: 2015

New data about the ground state of the Mn2+ impurity ions in a series of single crystals of alumbrados MAl3(BO3)4, where M = Y,Eu,Tm were obtained. The electron paramagnetic resonance (EPR) spectra of the Mn2+ spectra were studied, the parameters of the spin Hamiltonian describing the angular dependence of the spectrum were defined. It was shown that Mn2+ ions substitute trivalent ions of rare earth metals without changing the symmetry of the substitution site. The charge compensation process was found to be a nonlocal one. The cooling of the crystals leads to the increase of the splitting of the ground state, which is associated with the anisotropy of the thermal expansion coefficient. It was shown that an application of the superposition model to explain the distortions induced by an impurity Mn2+ ion has some limitations. The EPR linewidth of the Mn2+ ion in the TmAl3(BO3)4 crystal increases with increasing temperature as a result of the dipole-dipole and exchange interactions with the excited states of the host lattice Tm3+ ion. © 2015 The Royal Swedish Academy of Sciences. Source


Prokhorov A.D.,A A Galkin Donetsk Physico Technical Institute | Prokhorov A.A.,A A Galkin Donetsk Physico Technical Institute | Chernysh L.F.,A A Galkin Donetsk Physico Technical Institute | Aleshkevich P.,Polish Academy of Sciences | And 3 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2013

EPR spectra of impurity Nd 3+ and Er 3+ ions in aluminum borates YAl 3(BO 3) 4 and EuAl 3(BO 3) 4 have been studied. Dependences of g-factors and linewidth as a function of temperature are established, and the hyperfine interaction constants are determined. Temperature dependences of linewidth of Nd 3+ and Er 3+ ions in both crystals are identical. The absorption line broadening with increasing temperature is caused by strong spin-phonon interaction and is described by the Orbach-Aminov process. Unlike Nd 3+ ion, an anisotropy of temperature dependence of Er 3+ ion linewidth is observed. The relaxation velocity of Er 3+ ions is lower then that of Nd 3+ ions. The anisotropy of spin-lattice relaxation observed for Er 3+ ion is due to a large g-factor anisotropy which is larger in the EuAl 3(BO 3) 4 crystal than in YAl 3(BO 3) 4 one. A decrease of g-factor of Er 3+ ion in both crystals with increasing temperature is shown to result from spin-phonon interaction. Crown Copyright © 2012 Published by Elsevier B.V. All rights reserved. Source

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