Mohd Sobri Idris
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Preferred name
Mohd Sobri Idris
Official Name
Mohd Sobri , Idris
Alternative Name
Idris, Mohd Sobri
Idris, M. Sobri
Idris, M. S.
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Scopus Author ID
55898869500
Researcher ID
G-2128-2010

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  • Publication
    Electrical properties of Sn doped SrTiO₃
    (AIP Publishing, 2020-01)
    Muhammad Haniff Fisoldin
    ;
    Mohd Sobri Idris
    ;
    Rozana Aina Maulat Osman
    ;
    Ku Noor Dhaniah Ku Muhsen
    ;
    Zul Azhar Zahid Jamal
    The crystal structure and electrical properties of SrTiO₃ with addition of 50 mol% SnO2 was studied. Samples were prepared using conventional solid-state reaction route. The results indicate that Sn doped SrTiO₃ was single phase with cubic phase and space group Pm-3m after final sintering temparture at 1400°C. Two semicircular arcs clearly observed in Z" versus Z' plots for SrTi0.5Sn0.5O3 semicircles associated with bulk relaxation processes and grain boundary effect. The heterogeneity of sample was observed form Z' and M" spectroscopic plot. The highest dielectric constant is observed at much higher temperature which nearly 2000 at low frequency measurement.
  • Publication
    Colossal permittivity and dielectric behaviour of (Nb₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ and (Ta₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramics
    (Springer Nature, 2023)
    Ku Noor Dhaniah Ku Muhsen
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    The influence of pentavalent elements (Nb⁵⁺, Ta⁵⁺) with Fe³⁺ on TiO₂ ceramic were investigated. The (Nb₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ and (Ta₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramics have been synthesized and realized that the effect of Nb in the system has developed lattice expansion, although Nb and Ta exhibit similar ionic radii. The colossal permittivity value for (Nb₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramic is about εr ≥ 104 which is slightly higher than the (Ta₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramic. According to the dielectric analysis, both ceramics exhibit colossal permittivity below 10³ Hz which contributed by the electron-pinned defect-dipole (EPDD) model. However, the low εr values in the high-frequency region are associated with the internal barrier layer capacitor (IBLC) model. In addition, the grain boundary resistance is far greater than the grain resistivity (Rgb≫ Rg) which confirmed the existence of the IBLC effect by equivalent circuit analysis.
  • Publication
    Impedance and modulus spectroscopy of polycrystalline Ba0.9995La0.0005TiO3for multilayer ceramic capacitor
    ( 2021-07-21)
    Tiong Yuan Tze
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    ;
    Ku Noor Dhaniah Ku Muhsen
    ;
    Nurul Izza Mohd Nor
    ;
    Wahab Y.A.
    ;
    Sagadevan S.
    ;
    Sebastian T.
    ;
    Arturo R.L.D.
    Ba0.9995La0.0005TiO3 ceramics prepared via solid-state reaction route was found to be phase pure at the final sintering temperature of 1300°C for 16 hours. The dielectric constant was varied from 1900 to 2800 from 10 Hz to 100 kHz. Impedance spectroscopy is a powerful technique to study the complexities of ceramic materials such as homogeneity and inhomogeneity of materials that being process during production of most electronic materials. An electronic ceramic component can be visualized as a grain, grain boundary and electrode system. Impedance spectroscopy is being widely used to separate out contribution of the bulk and the grain boundary to the overall equivalent circuit models. Fixed frequency plots of dielectric constant versus temperature for Ba0.9995La0.0005TiO3 ceramics shows typical perovskite response with Curie temperature, Tc about 115 °C and fit with the equivalent circuit which contributed by bulk and grain boundary response.
      1  35
  • Publication
    Dielectric and structural analysis of hexagonal and tetragonal phase BaTiO3
    ( 2020-01-08)
    Nurul Huda Yusoff
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    ;
    Ku Noor Dhaniah Ku Muhsen
    ;
    Nurul Izza Mohd Nor
    Barium titanate (BaTiO3) has been synthesized using conventional solid state reaction method at sintering temperatures of 1150°C and 1400°C. A single phase tetragonal perovkite BaTiO3 was observed at 1150°C and changed to hexagonal phase at 1400a°C. The result was confimed by using X-ray diffraction analysis. Hexagonal BaTiO3 exhibits almost linear dielectric constant value between 60 to 120, however the tetragonal phase shows a phase transition from tetragonal to cubic at 120a°C. The tetragonal phase BaTiO3 has the highest dielectric constant 6000 at Tc and 4000 at room temperature.
      15  33
  • Publication
    Effect of Sn Doping on the Curie Temperature, Structural, Dielectric and Piezoelectric Properties of Ba0.8Sr0.2Ti1−xSnxO3 Ceramics
    ( 2023)
    Nadia Nasika Nasir
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    ;
    Ku Noor Dhaniah Ku Muhsen
    ;
    Prabakaran A/L Poopalan
    ;
    Nur Izzati Muhammad Nadzri
    ;
    Mohammad Hafizuddin Hj Jumali
    ;
    Nor Huwaida Jamil
    Ba0.8Sr0.2Ti1−xSnxO3 material with varying Sn concentrations (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.10) was synthesized using the conventional solid-state reaction method. X-ray diffraction (XRD) analysis reveals that as the Sn concentration increases from x = 0 to x = 0.10, the Ba0.8Sr0.2Ti1−xSnxO3 undergoes a structural phase change from tetragonal to cubic. Dielectric analysis of Ba0.8Sr0.2Ti1−xSnxO3 shows a significant drop in Tc, from 65 to 5°C, caused by the replacement of Sn4+ ions with larger ionic radii compared to Ti4+ ions at the B-sites. The composition with x = 0 exhibits the largest dielectric constant due to its enormous spontaneous dipole moments. Conversely, the substitution of Sn in Ba0.8Sr0.2Ti1−xSnxO3 reveals a decrease in the dielectric constant at the B-site structure of perovskite, resulting in a reduced tolerance factor and a decrease in the tetragonality of the sample. However, the pinching effect significantly enhances the dielectric constant of the sample with x = 0.10. Grain size measurements for x = 0 demonstrate a well-distributed grain structure. Additionally, the undoped sample exhibits a higher piezoelectric constant than the Ba0.8Sr0.2Ti1−xSnxO3 samples. According to the piezoelectric constant data, the composition with a tetragonal structure appears to have a greater piezoelectric constant than the cubic structure.
      1  39