| Summary: | In this work, we have prepared intergrowth of multiferroic compounds namely Bi<sub>4</sub>RTi<sub>3</sub>Fe<sub>0.7</sub>Co<sub>0.3</sub>O<sub>15</sub>-Bi<sub>3</sub>RTi<sub>2</sub>Fe<sub>0.7</sub>Co<sub>0.3</sub>O<sub>12−δ</sub> (BRTFCO<sub>15</sub>-BRTFCO<sub>12</sub>) (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: A2<sub>1</sub>am). Analysis of magnetic measurements confirmed a larger magnetization for theSm-modified intergrowth compound (BSTFCO<sub>15</sub>-BSTFCO<sub>12</sub>) compared to Dy- and La-doped ones. The emergence of higher magnetic properties can be due to distortion in the unit cell when some Bi<sup>3+</sup> ions are replaced with the Sm<sup>3+</sup>, bonding of Fe<sup>3+</sup>-O-Co<sup>3+</sup> as well as a possible mixture of Fe<sub>x</sub>Co<sub>y</sub>-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.
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