EPR Study of the Mn-Doped Magnesium Titanate Ceramics

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