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The solute-drag-dependent growth kinetics of core-shell-structured grains in rare-earth-doped BaTiO3 ceramics was studied based on an analytical description of the diffusion of rare-earth atoms doped. Dependence of the sizes of grain core and shell on the sintering conditions, dopant content, and starting powder size was quantitatively revealed. The effective dielectric constant of the ceramics was calculated in terms of the relative contents of the ferroelectric core and paraelectric shell. The calculations are in good agreement with the experimental observations. [ABSTRACT FROM AUTHOR]

We have investigated the relation between ferroelectric and magnetic orders of orthorhombic (o-) LuMnO3 ceramics. The increase of dielectric constant &eh; exceeds 82% near incommensurate to commensurate E-type antiferromagnetic (AFM) spin ordering transition temperature TL, reflecting a large magneto (thermo) dielectric response. Meanwhile, distinct anomalies and thermal hysteresis behavior are observed near this temperature in both temperature dependence of &eh; and specific heat Cp, indicating a strong coupling between FE and magnetic orders in o-LuMnO3. Comparing to o-HoMnO3, TmMnO3, and YbMnO3 with similar E-type AFM ground state, o-LuMnO3 has the largest magneto (thermo) dielectric effect [ABSTRACT FROM AUTHOR]