Low-temperature elastic properties of glasses in magnetic fields

Recently, the low-temperature dielectric susceptibility of several multicomponent glasses was found to vary strongly with applied dc magnetic field. In this paper we present the first measurements of the low-temperature elastic susceptibility of glasses in magnetic fields. Mechanical double paddle oscillators made of several multicomponent glasses (BK7, AF45) were used to measure the sound velocity and internal friction in fields up to 0.2 T and at temperatures down to 5 mK. No significant influence of the magnetic field on the acoustic properties was observed. This raises questions why tunneling states in glasses may exhibit a magnetic field dependence in the dielectric but not in the acoustic response.