Synthesis and Characterization of Terbium Iron Garnet for the NSR-Ferrimagnets Experiment

Rare-earth iron garnets are an example of Néel ferrimagnetism. Several of these materials exhibit temperature-dependent orbital cancellation of the magnetism associated with the electron spins, leaving a dense ensemble of polarized electrons which are of interest as a background-free source for exotic spin- dependent fifth-force searches. Neutrons can probe the internal state of the ferrimagnet at the compensation point, allowing for the search for spin-dependent forces in the NSR-Ferrimagnets Experiment at the HFIR CG-1D MARS neutron imaging beamline at ORNL. To prepare a sample for this experiment, we used a precipitation reaction to obtain the garnet phase, XRD analysis to determine the purity, magnetization to align the electron spins, and finally magnetometry to confirm the polarization and compensation point. We describe the process of polycrystalline sample synthesis and characterization, and the determination of the compensation point using external magnetometry on the NSR-Ferrimagnets apparatus.