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This study demonstrates a simple and cost-effective route to induce relaxor ferroelectric behavior in BaTiO3 (BTO) ceramics. Sintered pellets prepared from unmilled and milled BTO powders were characterized using Xray diffraction (XRD), dielectric spectroscopy, and P–E measurements. XRD confirmed the retention of the tetragonal P4mm phase in all samples. Dielectric spectra showed a clear evolution from a sharp Curie peak (~120 ◦C) in pellets obtained from unmilled powders to a broad diffuse transition (60 ◦C–180 ◦C) after milling; with the diffuseness coefficients increasing from 0.52 to 1.30. Piezoresponse force microscopy corroborated the formation of polar nanoregions in sintered pellets obtained from milled BTO. P–E loops exhibited the expected relaxor-type slim hysteresis, with reduced Pᵣ (1.32 μC/cm2) and Ec (5.69 kV/cm). Milling also improved functional performance, the recoverable energy density (Wrec) increased from 0.22 to 0.31 J/cm3, while the energy storage efficiency (η) increased from 15 % to 85 %.

BaTiO3-xNb (BTO-xNb) ceramics were prepared through high-energy milling. Initially, a total of 5 g of the BaTiO3 (99.9% Sigma Aldrich) mixture was combined with Nb2O5 (99.9% Sigma Aldrich) oxide powders at concentrations of x= 0, 0.025, 0.05, 0.075, and 0.1 weight ratio (wt.) %. The mixture powders and grinding media (steel balls), in a weight ratio of 10:1, were loaded into a steel vial at room temperature and under air atmosphere conditions. Subsequently, the powders were milled using a shaker mixer mill (SPEX model 8000D) at 1080 cycles per minute for 5 hours. After milling, the powder underwent pressing using a hydraulic press, with an application of 1400 MPa to produce 10 mm diameter pellets. These pellets were subjected to sintering at 1100 °C for 3 hours using a tubular muffle furnace (Lindberg Blue) within an atmosphere of air. This temperature was selected because higher temperatures produce liquid sintering, which is attributed to the energy imparted by the high-energy milling in complement with Nb dopant. This reduces the sintering temperature by enhancing particle surface activation. For the analysis of the crystal structure of the synthesized materials, X-ray diffraction was employed, utilizing a Bruker D8 Advance diffractometer with CuKα1 radiation (λ = 1.15418 Å); the XRD patterns were measured in a 2ϴ range from 20 to 80. Subsequently, for determination of the specific crystal structure, identification of present phases, and precise characterization of the lattice parameters obtained, XRD patterns underwent a Rietveld refinement analysis using Maud Software. The morphology of the particles was analyzed using a JEOL JSM-6300 scanning electron microscope. To analyze the dielectric and electric properties, the pellets were painted on both surfaces with silver paste, determining the relative permittivity, loss tangent, and electric conductivity at room temperature using an LCR Hioki 3532-50 at the frequency range from 50 to 5 X106 Hz. Ferroelectric hysteresis loops were obtained at room temperature using a ferroelectric RT66B-4 kV-HV workstation (Radiant Technologies) at 10 Hz. Finally, to determine the magnetic properties, magnetic the hysteresis loops were obtained at room temperature using a MicroSenseEV7 vibrating sample magnetometer (VSM) with a maximum field of ±1.8 kOe.

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Ceramics Synthesis, Barium Titanate, Ferroelectricity, Ferromagnetism, Multiferroic Material

Creative Commons Attribution 4.0 International

This study demonstrates a simple and cost-effective route to induce relaxor ferroelectric behavior in BaTiO3 (BTO) ceramics. Sintered pellets prepared from unmilled and milled BTO powders were characterized using Xray diffraction (XRD), dielectric spectroscopy, and P–E measurements. XRD confirmed the retention of the tetragonal P4mm phase in all samples. Dielectric spectra showed a clear evolution from a sharp Curie peak (~120 ◦C) in pellets obtained from unmilled powders to a broad diffuse transition (60 ◦C–180 ◦C) after milling; with the diffuseness coefficients increasing from 0.52 to 1.30. Piezoresponse force microscopy corroborated the formation of polar nanoregions in sintered pellets obtained from milled BTO. P–E loops exhibited the expected relaxor-type slim hysteresis, with reduced Pᵣ (1.32 μC/cm2) and Ec (5.69 kV/cm). Milling also improved functional performance, the recoverable energy density (Wrec) increased from 0.22 to 0.31 J/cm3, while the energy storage efficiency (η) increased from 15 % to 85 %.

BaTiO3-xNb (BTO-xNb) ceramics were prepared through high-energy milling. Initially, a total of 5 g of the BaTiO3 (99.9% Sigma Aldrich) mixture was combined with Nb2O5 (99.9% Sigma Aldrich) oxide powders at concentrations of x= 0, 0.025, 0.05, 0.075, and 0.1 weight ratio (wt.) %. The mixture powders and grinding media (steel balls), in a weight ratio of 10:1, were loaded into a steel vial at room temperature and under air atmosphere conditions. Subsequently, the powders were milled using a shaker mixer mill (SPEX model 8000D) at 1080 cycles per minute for 5 hours. After milling, the powder underwent pressing using a hydraulic press, with an application of 1400 MPa to produce 10 mm diameter pellets. These pellets were subjected to sintering at 1100 °C for 3 hours using a tubular muffle furnace (Lindberg Blue) within an atmosphere of air. This temperature was selected because higher temperatures produce liquid sintering, which is attributed to the energy imparted by the high-energy milling in complement with Nb dopant. This reduces the sintering temperature by enhancing particle surface activation. For the analysis of the crystal structure of the synthesized materials, X-ray diffraction was employed, utilizing a Bruker D8 Advance diffractometer with CuKα1 radiation (λ = 1.15418 Å); the XRD patterns were measured in a 2ϴ range from 20 to 80. Subsequently, for determination of the specific crystal structure, identification of present phases, and precise characterization of the lattice parameters obtained, XRD patterns underwent a Rietveld refinement analysis using Maud Software. The morphology of the particles was analyzed using a JEOL JSM-6300 scanning electron microscope. To analyze the dielectric and electric properties, the pellets were painted on both surfaces with silver paste, determining the relative permittivity, loss tangent, and electric conductivity at room temperature using an LCR Hioki 3532-50 at the frequency range from 50 to 5 X106 Hz. Ferroelectric hysteresis loops were obtained at room temperature using a ferroelectric RT66B-4 kV-HV workstation (Radiant Technologies) at 10 Hz. Finally, to determine the magnetic properties, magnetic the hysteresis loops were obtained at room temperature using a MicroSenseEV7 vibrating sample magnetometer (VSM) with a maximum field of ±1.8 kOe.

, ,

Ceramics Synthesis, Barium Titanate, Ferroelectricity, Ferromagnetism, Multiferroic Material

Creative Commons Attribution 4.0 International