EPR Study of the Mn-Doped Magnesium Titanate Ceramics

Abstract

Manganese-doped magnesium titanate ceramic samples obtained by a solid-state reaction via sintering in the air from a mixture of MgO and TiO2 powders of different molar ratios were analyzed by electron paramagnetic resonance (EPR) technique. The EPR signals of Mn2+ ions (S = 5/2, І = 5/2) in crystal phases of MgO, Mg2TiO4, and MgTiO3 were detected. We have obtained the following spin Hamiltonian parameters for Mn2+ ions: g = 2.0015, A ∼81.0 × 10−4 cm−1 (in MgO phase); g = 2.0029, A ∼73.8 × 10−4 cm−1 , b 2 0 = 35 × 10−4 cm−1 (in Mg2TiO4 phase); g = 2.0040, A ∼79.0 × 10−4 cm−1 , b 2 0 = 165 × 10−4 cm−1 (in MgTiO3 phase). Despite the presence of Mn4+ centers in both Mg2TiO4:Mn and MgTiO3:Mn ceramics confirmed by previous optical studies, no EPR signals related to Mn4+ ions (S = 3/2, І = 5/2) were found. The Mn2+ EPR signals are proposed as structural probes in manganese-doped magnesium titanate ceramics.