Dielectric, magnetic, ferroelectric, and Mossbauer properties of bismuth substituted nanosized cobalt ferrites through glycine nitrate synthesis method.

CoFe_2-xBi_xO₄ nanoferrites with x=0, 0.05, 0.1, 0.5, and 1.0 have been synthesized by the glycine nitrate process. The present study investigates the effect of Bi³⁺ substitution on the microstructural, dielectric, ferroelectric, magnetic, and Mossbauer properties of CoFe₂O₄ nanoparticles. The X-ray diffraction technique was used to confirm the phase purity and estimate the crystallite size which revealed the formation of a secondary phase when Bi³⁺ concentration exceeds x=0.5. Transmission electron microscopy indicated the formation of grains by aggregation of small crystallites with a reduction in grain size to 20nm with an increase in Bi³⁺ content and also divulged the lattice parameter value to be 8.378Å , confirming the crystalline nature of the synthesised sample. Dielectric properties performed in the frequency range of 100Hz to 1MHz determined that the dielectric behavior is attributed to the Maxwell-Wagner polarization and the activation energy of the specimens is calculated from the dielectric measurements. The hysteresis curve indicated the ferrimagnetic nature of the samples. The samples also exhibited a well saturated P-E loop with gradual lowering in remenant polarization, coercive field, and saturation polarization with an increase in bismuth concentration. Mössbauer spectroscopy analysis confirmed the changes in magnetic moment of ions, their coupling with neighbouring ions, and cation exchange interactions. Owing to the high physical, thermal, and chemical stabilities, these magnetic ceramics, CoFe₂-xBi_xO₄, possesses tremendous potential in major understanding of magnetism and in magnetic recording applications for high density information storage. [ABSTRACT FROM AUTHOR]