A novel technique for measuring the magnetic susceptibility of liquids with modest applied magnetic fields (order of 0.25 T) is presented. The deformation of the liquid surface by a magnetic field is determined by a laser bounce or optical lever technique. The energy balance between the magnetic energy and the gravitational potential of the diamagnetic or paramagnetic liquid interaction is used to determine the susceptibility. The energy due to the surface tension energy is about 10 of the gravitational energy and can be neglected for fast measurements.
Bibliographical noteFunding Information:
Steve Pullar and Kurt Wick contributed to the development of the apparatus and measurement technique. We thank Daniel Endean for discussions on the analysis of the data. This work was supported by the MRSEC Program of the National Science Foundation under Award No. DMR-0819885, the University of Minnesota MRSEC RET program, and the University of Minnesota UROP program. We also thank the Characterization Facility at the University of Minnesota for help with the surface tension measurement.