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In this work, we have prepared intergrowth of multiferroic compounds namely Bi4RTi3Fe0.7Co0.3O15-Bi3RTi2Fe0.7Co0.3O12−δ (BRTFCO15-BRTFCO12) (rare earth (R) = Dy, Sm, La) by solid-state reaction method. From the X-ray diffraction Rietveld refinement, the structure of the intergrowths was found to be orthorhombic in which satisfactory fittings establish the existence of three-layered (space group: b 2 c b) and four-layered compounds (space group: A21am). Analysis of magnetic measurements confirmed a larger magnetization for theSm-modified intergrowth compound (BSTFCO15-BSTFCO12) compared to Dy- and La-doped ones. The emergence of higher magnetic properties can be due to distortion in the unit cell when some Bi3+ ions are replaced with the Sm3+, bonding of Fe3+-O-Co3+ as well as a possible mixture of FexCoy-type nanoparticles that are formed generally in the synthesis of intergrowths. The changes in the magnetic state of the Aurivillius intergrowths have been reflected in the magnetoelectric (ME) coupling: higher ME coefficient (~30 mV/Cm-Oe) at lower magnetic fields and is constant up to 3 kOe. The results were corroborated by Raman spectroscopy and variation of temperature with magnetization data. The results revealed that the RE-modified intergrowth route is an effective preparative method for higher-layer Aurivillius multiferroic ceramics.

Spark Plasma Sintering (SPS) technique was employed to synthesize 0.75BaTiO3-0.25BaFe12O19 composite. X-ray diffraction studies revealed that the composite consisted of both BaTiO3 (ferroelectric phase) andBaFe12O19 (ferrimagnetic phase), respectively. The SPS treated sample showed improved ferroelectric nature when compared to conventional sintered (CS) sample. Transformation from hard to soft magnetic nature was envisaged by magnetization measurements for SPS sample. A slim hysteresis loop was recorded with a low coercivity values (390 Oe) when compared to CS sample (3900 Oe). Mossbauer spectroscopy analysis indicated that the existence of a partial amount of γ-Fe2O3 phase in the lattice, giving rise to soft magnetic nature. The SPS sample showed slightly higher value of magnetoelectric output of 2.95 mV/cm at 3 kOe magnetic field when compared to the CS sample (1.45 mV/cm at 3 kOe). The present investigation compares the spark plasma sintered sample with the conventional sintered sample.