Structural and magnetic properties of MnO-B2O3-SrO glasses

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