Spin-phonon coupling mediated magneto-dielectricity in indium doped barium hexaferrite (BaFe10.5In1.5O19)

The present work reports the room temperature crystal and magnetic structure, temperature dependent magnetization, Raman spectroscopy and dielectric studies of the polycrystalline indium doped barium hexaferrite (BaFe_10.5In_1.5O₁₉). Room temperature neutron diffraction measurement shows that the prepared sample is in single phase and possesses a ferrimagnetic structure. The magnetization versus temperature (χ-T) measurement revealed that the sample undergoes paramagnetic to ferrimagnetic transition at around 410 K. High temperature Raman spectroscopy shows distinct changes in the modes around the magnetic ordering temperature establishing the presence of strong spin phonon coupling. Dielectric studies also showed the anomaly around the magnetic transition, which is a clear signature of magneto dielectric coupling at 410 K. The system thus shows coupling between magnetic and dielectric properties mediated through the spin-phonon coupling.