Structural investigation and improvement of microwave dielectric properties in Ca(HfxTi1-x)O3 ceramics

Zaman, Abid; Uddin, Sarir; Mehboob, Nasir; Ali, Asad

doi:10.1088/1402-4896/abce74

Cited by 30 publications

(22 citation statements)

References 27 publications

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“…The reason for this is the variation of the ionic radii of Zn 2+ (0.60 Å), Co 2+ (0.58 Å), and Cu 2+ (0.73 Å). We have determined the average crystal size by using Debye Scherer’s equation 22 where, λ is the wavelength of the incident radiation, that is, 1.45 Å, β is the full width at half maximum (FWHM) of the (101) peak, and θ is Bragg’s angle.…”

Section: Resultsmentioning

confidence: 99%

Room-Temperature Ferromagnetism in Cu/Co Co-Doped ZnO Nanoparticles Prepared by the Co-Precipitation Method: For Spintronics Applications

et al. 2022

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In current work, pure ZnO and Zn 0.96– x Cu 0.04 Co x O (0 ≤ x ≤ 0.05) nanoparticles were synthesized by the co-precipitation method. Structural analysis and phase determination of the formed nanoparticles was carried out using X-ray diffraction (XRD) and Williamson–Hall plots. The hexagonal wurtzite structure was manifested by all the samples with divergent microstructures. The change in lattice parameters, bond length, dislocation density, and lattice strain indicates that Cu and Co were successfully incorporated. Average crystallite size was found to be in the range of 32.16–45.42 nm for various doping concentrations. Field emission scanning electron microscopy results exhibited that the surface morphology is an amalgam of spherical-like and hexagon-like structures. Spherical-shaped grains were homogeneous and evenly distributed all over the structure. Fourier transform infrared spectra indicated that the absorption bands were blue-shifted with increasing Co concentration. The UV–visible absorption spectra showed high absorption in the UV region and weak absorption in the visible region. An increase in the energy band gap for the maximum absorption peak was observed from 3.49 eV for ZnO to 3.88 eV for Zn 0.91 Cu 0.04 Co 0.05 O. The Burstein–Moss effect explained the noticed blue shift in absorption spectra and energy band gaps. The vibrating sample magnetometer study revealed the change in the diamagnetic behavior of pure ZnO to the ferromagnetic behavior of the prepared nanoparticles at room temperature for different doping concentrations. In the current study, we have developed the room-temperature ferromagnetism (RTFM) for Cu and Co co-doped ZnO nanoparticles. Since RTFM is the key objective for dilute magnetic semiconductors, therefore it can be served as the desirable expectant for spintronics applications with improved functionalities and device concepts.

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Section: Resultsmentioning

confidence: 99%

Room-Temperature Ferromagnetism in Cu/Co Co-Doped ZnO Nanoparticles Prepared by the Co-Precipitation Method: For Spintronics Applications

et al. 2022

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“…where d x is X-ray density and d m is mass density [40]. The lattice parameters, average crystallite sizes, X-ray density, mass density, and porosity are given in Table 1.…”

Section: Structural Analysismentioning

confidence: 99%

Synthesis and Characterization of Ce3+-Doped Ni0.5Cd0.5Fe2O4 Nanoparticles by Sol–Gel Auto-Combustion Method

et al. 2021

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Cerium (Ce)-doped Ni0.5Cd0.5CexFe2−xO4 (0.0 ≤ x ≤ 0.20) was synthesized using the sol–gel auto-combustion method. X-ray diffraction (XRD) analysis revealed that all the samples retained spinel cubic crystal structure with space group Fd3m at 800 °C. Crystal structure parameters, such as lattice constant, average crystallite size, and X-ray density were estimated from the major XRD (311) peak. Bulk density and porosity were also calculated. The average crystallite size was estimated to be in the range of 20–24 nm. SEM images displayed agglomerated particles with a porous morphology. The dielectric constant (ε′) increased and the dielectric loss tangent (tanδ) decreased with rising Ce concentration. The hysteresis loop (M–H loop) was measured at room temperature using a vibrating-sample magnetometer (VSM), which showed a nonlinear decrease in magnetization and coercivity with increasing Ce concentration.

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“…The dislocation density can be determined with 19 where δ is the dislocation density while D is the crystallite size.…”

Section: Resultsmentioning

confidence: 99%

Effects of Strontium on the Structural, Optical, and Microwave Dielectric Properties of Ba₂Ti₉O₂₀ Ceramics Synthesized by a Mixed Oxide Route

et al. 2022

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Solid solutions of Sr-doped barium nonatitanate (Ba 2 Ti 9 O 20 ) ceramics were synthesized by a mixed oxide route, studied their structural, microstructural, optical, and microwave dielectric properties were studied. X-ray diffraction (XRD) has been used to reveal the structure and crystallite size of doped Ba 2 Ti 9 O 20 ceramics. Rietveld refinements of XRD patterns revealed that all of the ceramics have a tetragonal structure with space group I 4/ m . The surface morphologies of all the samples were characterized by using scanning electron microscopy (SEM). Fourier transform infrared (FT-IR) studies gave the O–H and Ti–O modes of vibrations. The stretching modes of Ti–O and O–H were noted at 1400, 2960, 3700, and near to 440 cm –1 , respectively. The band gap energy decreases with increasing Sr 2+ contents, and a high value (2.12 eV) was observed in the base sample. The microwave dielectric properties of the ceramic samples were studied at different frequencies ranging from 1 to 2 GHz by using impedance spectroscopy. The obtained results showed the suitability of these samples for microwave dielectric resonator (antenna) applications.

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Structural investigation and improvement of microwave dielectric properties in Ca(HfxTi1-x)O3 ceramics

Cited by 30 publications

References 27 publications

Room-Temperature Ferromagnetism in Cu/Co Co-Doped ZnO Nanoparticles Prepared by the Co-Precipitation Method: For Spintronics Applications

Room-Temperature Ferromagnetism in Cu/Co Co-Doped ZnO Nanoparticles Prepared by the Co-Precipitation Method: For Spintronics Applications

Synthesis and Characterization of Ce3+-Doped Ni0.5Cd0.5Fe2O4 Nanoparticles by Sol–Gel Auto-Combustion Method

Effects of Strontium on the Structural, Optical, and Microwave Dielectric Properties of Ba₂Ti₉O₂₀ Ceramics Synthesized by a Mixed Oxide Route

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Structural investigation and improvement of microwave dielectric properties in Ca(HfxTi1-x)O3 ceramics

Cited by 30 publications

References 27 publications

Room-Temperature Ferromagnetism in Cu/Co Co-Doped ZnO Nanoparticles Prepared by the Co-Precipitation Method: For Spintronics Applications

Room-Temperature Ferromagnetism in Cu/Co Co-Doped ZnO Nanoparticles Prepared by the Co-Precipitation Method: For Spintronics Applications

Synthesis and Characterization of Ce3+-Doped Ni0.5Cd0.5Fe2O4 Nanoparticles by Sol–Gel Auto-Combustion Method

Effects of Strontium on the Structural, Optical, and Microwave Dielectric Properties of Ba2Ti9O20 Ceramics Synthesized by a Mixed Oxide Route

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Effects of Strontium on the Structural, Optical, and Microwave Dielectric Properties of Ba₂Ti₉O₂₀ Ceramics Synthesized by a Mixed Oxide Route