Low-temperature elastic properties of glasses in magnetic fields

Recently, the low-temperature dielectric susceptibility of several multicom ponent glasses was found to vary strongly with applied de magnetic field In this paper we present the first measurements of the low-temperature elasti c susceptibility, of glasses in magnetic fields. Mechanical double paddle o scillators made of several multicomponent glasses ( BK7, AF45) were used to measure the sound velocity and internal friction fields zip to 0.2 T and a t temperatures down to 5 mK. No significant influence of the magnetic field on the acoustic properties was observed. This raises questions why tunneli ng states in glasses may exhibit a magnetic field dependence in the dielect ric but not in the acoustic response.