Magnetoelectric and magnetodielectric effect in Ba1−xSrxTiO3 and Co0.9Ni0.1Fe2−xMnxO4 composites

Ba1−xSrxTiO3 (BST) is a ferroelectric material known to possess ferroelectric transition temperature Tc in the vicinity of room temperature ∼30 °C for x = 0.3. As the BST with x in the vicinity of 0.3 is elastically soft at 30 °C, the compositions with x = 0.2, 0.25 and 0.3 are chosen to investigate their possible magnetoelectric (ME) and magnetodielectric (MD) applications. The (CoNi) FeMn2O4 (CNFMO) is selected to be a piezo-magnetic phase. Here hydroxide co-precipitation route is adopted so as to synthesize BST and CNFMO of nearly 100 nm crystallite size. Starting with the BST and CNFMO powders, the composites yCNBST = yCNFMO + (1 − y) BST are synthesized for y = 0.3 and 0.4. The parent compositions of BST as well as the CNFMO are characterized for dielectric and magnetic properties to confirm the formation of the desire ferroelectric and magnetostrictive phases. The composites are investigated for the crystal structure, dielectric, magnetoelectric and magnetodielectric properties. The results show that the composite Ba0.75Sr0.25TiO3–Co0.9Ni0.1Fe1.7Mn0.3O4 exhibit excellent ME and MD properties simultaneously. The results on the ME and MD properties are understood in terms of the stress induced variations in polarization and dielectric constant ɛ respectively.

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