Electron magnetic resonance studies of the Pr3Ga5SiO14 and Nd3Ga5SiO14 kagomé systems

We report low-temperature, high-frequency (50–800 GHz) electron magnetic resonance measurements on single crystals of the antiferromagnetic kagomé lattice compounds Nd3Ga5SiO14 and Pr3Ga5SiO14. The obtained spectra are extremely rich, displaying a large number of sharp peaks whose positions exhibit a strong systematic temperature dependence. In contrast, the spectra do not seem to follow any systematic dependence on the microwave frequency. …