Non-linearities and magnetic field dependencies of the dielectric constant of BaO • Al2O3 • SiO2

We report measurements at 1 kHz of the dielectric constant and dielectric loss of the multi-component glass BaO - Al2O3 - SiO2 in the temperature range between 27 and 520 mK. A strong non-monotonic dependence of both quantities on an external magnetic field is observed which becomes larger with decreasing temperature. At lowest temperatures, the relative change of the dielectric constant is of the order of 10(-4). The magnetic field dependence changes considerably when the strength of the driving electric AC field is altered. This demonstrates a close entanglement of the action of the electric AC field and the static magnetic field. (C) 2002 Elsevier Science B.V. All rights reserved.