Structural and magnetic properties of MnO-B2O3-SrO glasses

The Mn2+ ion distribution in different structural units in 2B(2)O(3). SrO glasses was revealed by means of electron paramagnetic resonance measurements. Octahedral symmetric sites, tetragonally distorted, were detected and also the progressive clustering of Mn2+ ions above a certain impurity level (x greater than or equal to 10 mol % MnO). Magnetic measurements revealed that both Mn2+ and Mn3+ ionic species are simultaneously present in the matrix and that a transition from magnetically isolated ions to antiferromagnetically coupled pairs occurs on increasing the manganese content over 10 mol % MnO. (C) 1999 Kluwer Academic Publishers.