Magneto-optical properties of Eu2+-containing aluminoborosilicate glasses with ferromagnetic interactions

Abstract Magnetic, optical, and magneto-optical properties have been examined for aluminoborosilicate glasses with high concentration of divalent europium ions. An analysis on temperature dependence of magnetic susceptibility yields positive Weiss temperatures, indicating that magnetic moments of 4f electrons of Eu2+ interact ferromagnetically with each other in the glasses. The glasses show large Faraday rotation angles in the visible range; glass with a composition of 58.0EuO·12.0Al2O3·20.0B2O3·10.0SiO2 (mol%) has a Verdet constant of −1.03 min/Oe cm (−300 rad/T m) at 633 nm. Wavelength dependence of the Verdet constant is interpreted in terms of Eu2+ 4f7 to 4f65d1 electronic transitions based on the Van Vleck–Hebb theory.