Fabrication of submicron BaTiO_3@YFeO_3 particles and fine-grained composite magnetodielectric ceramics with a core-shell structure by means of a co-precipitation method

摘要

The submicron BaTiO_3@YFeO_3 particles (diameter about 240 nm) with core-shell structure using a co-precipitation method were prepared. We obtained fine-grained BaTiO_3@YFeO_3 composite magnetodielectric ceramics (grain size ≤250 nm) with a tetragonal-phase BaTiO_3 core and an orthorhombic-phase YFeO_3 shell by means of sintering at a low temperature (1180 °C) in air. The temperature coefficient of capacitance characteristic (TCC) of the BaTiO_3@YFeO_3 ceramics satisfied the X8R specification. As the YFeO_3 content increased from 2.0 to 8.0 mol%, the room-temperature permittivity of the samples first increased and then decreased, and the maximum room-temperature permittivity was 2319 at 6.0 mol% YFeO_3, and a low dielectric loss at room temperature (<0.020). The saturation magnetization (M_s) and remnant magnetization (M_r) increased as the YFeO_3 content increased, reaching values of 2.74 and 1.75 emu/g, respectively, at 8.0 mol% YFeO_3. The improved microstructure and properties of BaTiO_3@YFeO_3 materials indicated that the co-precipitation approach represents a good way to prepare such materials for use in multifunctional devices.