Sensitivity limits to ferrimagnetic Faraday effect magnetic field sensors

In general, the sensitivity of ferrimagnetic Faraday effect magnetic field sensors is a function of both the crystal geometry and composition. The geometrical dependence of the sensitivity in nonellipsoidal crystals, such as cylinders, is complicated by their spatially nonuniform demagnetizing factors. We compare sensitivity data obtained from a variety of cylindrical iron garnet samples with models which predict the effective demagnetizing factor Neff as a function of the length-to-diameter ratio. With respect to composition, we present experimental results of sensitivity vs diamagnetic substitution (x) in the iron garnet series Y3Fe5−xGaxO12. As expected, the sensitivity rises sharply as x approaches the compositional compensation point.