Raman spectroscopy study and dielectric anomalies in Bi1-xEux AFM FeO3 thin films

BiFeO3 is a multiferroic material, so its ferroelectric and ferromagnetic properties are coupled. Due to the presence of magneto-electric coupling in the system, magnetic changes are obvious in the dielectric spectra. As a thin film of BFO exhibits a weak magnetic moment, dielectric analysis can be utilized to observe different magnetic transitions. In the present work, thin films of Eu3+ substituted BiFeO3 are prepared to stabilize the Perovskite phase. The role of Eu3+ substitution in triggering the structural phase transformation is analyzed using Raman analysis. Capacitance and dissipation spectrum as a function of temperature for various Eu3+ concentrations are studied in detail. The presence of various transitions is observed in the dielectric permittivity. The possible origin of the transitions in permittivity spectra is discussed in terms of spin-lattice and charge interactions and their degrees of freedom. Substitution with rare-earth ions significantly affects the system's magnetic characteristic, including contribution from magnetization from sub-lattice and magnetic anisotropy. Eu3+ substitution led to the change in the spin reorientation axis, which has been explained in terms of phenomenological and microscopic variation in magnetization due to the contribution from the rare earth ion.