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EPR investigation of manganese ions in B2O3·BaO glass matrix

M. TODERAŞ1,2, I. ARDELEAN1,*

Affiliation

  1. Faculty of Physics, Babeş-Bolyai University, 400084 Cluj-Napoca, Romania
  2. Faculty of Science, Department of Physics, University of Oradea, 410087 Oradea, Romania

Abstract

Glasses of the xMnO·(100-x)[3B2O3·BaO] system, with 0.5≤x≤50 mol% were prepared and investigated by EPR measurements. Information concerning the structural details of the vitreous matrix revealed by Mn2+ paramagnetic ions distribution on different structural units building the network and coordination were obtained. EPR absorption spectra due to Mn2+ ions were detected for all the investigated samples. The distribution of the Mn2+ ions on several structural units of vitreous matrix revealed by EPR spectra structure depends on the MnO content. In the low concentration range isolated Mn2+ ions were identified in sites of slightly tetragonally distorted octahedral symmetry. They give rise the absorption centered at geff ≈2.0 showing a resolved hyperfine structure up to 5 mol% MnO. There are also isolated Mn2+ ions in sites of heavily distorted octahedral symmetry but with strong crystalline fields giving rise to absorption at geff ≈4.3. Their intensity is small enough comparatively with those centered at geff ≈ 2.0 indicated a relatively low concentration of Mn 2+ ions involved in such structural units. In the high concentration range, 10 ≤ x ≤ 50 mol% the progressive clustering of Mn 2+ ions was evidenced by the evolution of the corresponding absorption line at geff ≈2.0. Its line-width depends on concentration showing a dipolar broadening within 0.5 ≤ x ≤ 10 mol% and superexchange narrowing for x ≥ 10 mol%..

Keywords

Barium-borate glasses, EPR, Manganese ion.

Submitted at: Nov. 15, 2006
Accepted at: March 15, 2007

Citation

M. TODERAŞ, I. ARDELEAN, EPR investigation of manganese ions in B2O3·BaO glass matrix, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 3, pp. 629-632 (2007)