Nuclear Magnetic Dipole Frequency Shifts in a 3He-129Xe Comagnetometer

We report on the operation of a $^3$He-$^{129}$Xe comagnetometer in 2-mm sized anodically bonded cells with a 300 s spin coherence time for $^{129}$Xe. We use a series of batch-fabricated cells with well-defined cylindrical geometries to measure the frequency shifts due to nuclear magnetic dipole fields. We find that these frequency shifts, which cause instabilities in the operation of vapor-cell comagnetometers, can be nulled out in certain geometries. Using this control we investigate the isotropic spin-spin coupling between the two noble-gas nuclei.