EPR and FT-IR spectroscopic studies of B2O3Bi2O3MnO glasses

EPR and FT-IR absorption measurements performed on xMnO⋅(100−x)[B2O3⋅Bi2O3] glasses with 0⩽x⩽50 mol% are reported. The EPR spectra of all investigated samples exhibit resonance signals that are characteristic for the Mn2+ ions. For x⩽20 mol% the spectra consists of two resonance lines centered at geff≅4.3 and geff≅2.0, their relative intensity depending on the manganese content of the sample. For x⩽3 mol%, the line from geff≅4.3 has a resolved hyperfine structure characteristic for isolated Mn2+ ions disposed in distorted sites of an octahedral symmetry. The resonance line centered at geff≅2.0 has not hyperfine structure and is attributed to coupled Mn2+ ions by dipolar (x⩽5 mol%) or/and superexchange interactions (x>5 mol%).The FT-IR data indicate the presence in the glasses of the BO3, BO4, BiO6 and BiO3 units and its dependence on the MnO content.