“…For higher concentrations of Fe 2 O 3 , these data indicate that the iron ions in the glasses experience negative superexchange interactions and are predominantly antiferromagnetically coupled. Therefore, in the 3B 2 O 3 Á BaO glass matrix, the iron ions behave magnetically similarly as in other oxide glasses [4][5][6][7][8][9]. The increase of melting temperature determines the increase of the disorder in the S2 glasses, which are reflected in appearance by the magnetic superexchange interactions between iron ions at higher Fe 2 O 3 content.…”