Magnetic resonance study of rare-earth titanates

Rare-earth titanates are model systems for investigations of the interplay among spin, orbital, and lattice degrees of freedom. Ground-state magnetic order, through subtle lattice distortions, is easily manipulated by the size of the rare-earth ion. Peculiar deviations from the Curie-Weiss law and anomalous magnetic behavior have been detected well above the ferromagnetic ordering temperature in the Mott-insulating parent compound YTiO₃. We utilize magnetic resonance (NMR, ESR) techniques to explore these discrepancies. All measurements are conducted on single-crystalline samples of (Y, La, Ca)TiO₃ [1] in wide ranges of charge (Ca) doping and isovalent (La) substitution. NMR confirms the existence of anomalies in the paramagnetic phase of these compounds. X-band ESR measurements detect a small splitting of the lower t_2g orbital which scales with the sample T_c and could explain the unusual properties. We also directly measure the crystalline anisotropies of YTO₃ in the magnetically ordered state using ferromagnetic resonance.

[1] S. Hameed et al. 10.1103/PhysRevMaterials.5.125003