Electron paramagnetic resonance of manganese-doped strontium titanate

Ressonância paramagnética eletrônica de titanato de estrôncio dopado com manganês

Abstract

Electron paramagnetic resonance (EPR) spectra of manganese-doped strontium titanate were investigated for several Mn concentrations. The spectra of Mn²⁺ and Mn⁴⁺ ions were observed and attributed, respectively, to Mn ions occupying Sr²⁺ and Ti⁴⁺ sites. The relative intensity of the spectra suggested that the manganese ions occupy preferentially Ti⁴⁺ sites. The results showed that the EPR peak-to-peak linewidth of the Mn⁴⁺ spectrum increases with manganese concentration according to the theoretical equation DH_pp=0.45+210.f.(1-f)⁸⁰ (mT). This suggested that the exchange interaction between tetravalent manganese ions in strontium titanate has an approximate range of 0.96 nm, comparable to that of Gd³⁺ in the same compound.

Keywords:
ceramics; electron paramagnetic resonance; strontium titanate; manganese