Rozana Aina Maulat Osman
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Preferred name
Rozana Aina Maulat Osman
Official Name
Rozana Aina, Maulat Osman
Alternative Name
Osman, R. A.M.
Osman, A. Rozana
Maulat Osman, Rozana Aina
Osman, Rozana A.M.
Osman, R.
Osman, R. A.Maulat
Main Affiliation
Scopus Author ID
37261764900
Researcher ID
DXB-4277-2022

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  • Publication
    Influence of heating temperature on structure, morphology and electrochemical performance of LiV₃O₈ cathode for lithium-ion batteries application
    (Trans Tech Publications Ltd., 2020)
    Mohamad Izha Ishak
    ;
    Khairel Rafezi Ahmad
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    LiV₃O₈ layered structure was successfully synthesized by a conventional solid-state approach and subsequent heat-treated at 400, 450, 500 and 550 ºC. The samples were characterized by XRD, SEM, TEM, BET. Electrochemical performance of LiV₃O₈ was investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge. The results showed that high purity of LiV3O8 with layered structure was formed. The morphology of the samples were mixed between nanorods and nanosheets structure. For electrochemical performance, results showed that LiV₃O₈ heat-treated at 500 ºC performed a highest charge and discharge capacity of 212 and 172 mAh g-1, respectively. From electrochemical performance results made them a good candidate for cathode material for lithium-ion batteries application.
  • Publication
    Facile synthesis of layered LiV₃O₈ nanosheets and their electrochemical performance as cathode materials for Li-Ion batteries
    (Springer, 2020-03)
    Mohamad Izha Ishak
    ;
    Mohd Sobri Idris
    ;
    Rozana Aina Maulat Osman
    ;
    S. M. Hasanaly
    ;
    A. H. Hashim
    ;
    M. F. Rosle
    ;
    Khairel Rafezi Ahmad
    Layered nanosheets of a LiV₃O₈ cathode material were successfully prepared via a modified solid-state synthesis. The morphological changes of the layered nanosheets of the LiV₃O₈ cathode, which resulted from preparation at different temperatures, strongly affected the electrochemical performance of this cathode material. The layered nanosheets of the LiV₃O₈ cathode prepared at 500 °C delivered the highest electrochemical performance with initial charge and discharge capacities of 212 and 175 mAh g−1, respectively, when cycled between 1.5 and 4.0 V versus Li/Li+. The particulate morphology of LiV₃O₈ showed widths in a range of 100-145 nm and lengths between 1.0 and 2.5 µm. The layered nanosheet structure contributed to the increased electrochemical performance of LiV₃O₈ as a cathode material for applications in high-energy lithium-ion batteries.
  • 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
    Microwave and electrical properties of SrTiO3 for DRA application
    (Universiti Malaysia Perlis (UniMAP), 2018-12)
    Norhizatol Fashren Muhamad
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    ;
    Mohd Najib Mohd Yasin
    ;
    Mohd Faizal Jamlos
    ;
    Nor Azura Malini Ahmad Hambali
    ;
    Mohd Nazree Derman
    Appropriate level of dielectric constant and low dielectric loss are basic requirements for microwave device, especially in dielectric resonator antenna (DRA). In this paper, investigation with experimental studies of SrTiO₃ ceramic fabricated as cylindrical dielectric resonator antennas (CDRAs) was conducted. Ceramic powder was prepared using conventional solid state reaction method. X-ray Diffraction exposes physical properties SrTiO₃ which exhibit cubic structure. The electrical properties such as dielectric constant (εᵣ) and dielectric loss (tan δ) were studied in variation of temperatures and frequencies. At room temperature the dielectric constant SrTiO₃ is about 240. The dielectric loss obtain shows very low loss value roughly below 0.07. The return loss and bandwidth of CDRAs at their respective resonant frequencies are shown in this paper.
  • 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
    Structural and electrical properties of Barium Titanate (BaTiO3) and Neodymium doped BaTiO3 (Ba0.995Nd0.005TiO3)
    ( 2017)
    Tuan Amirah Tuan Sulong
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    ;
    Zul Azhar Zahid Jamal
    Barium titanate (BaTiO3) and Neodymium (Nd) doped BaTiO3 with composition Ba0.995Nd0.005TiO3 were prepared using conventional solid state reaction method to study the dielectric properties of materials. Pure phase samples were found at final heating temperature of 1400°C for overnight. X-ray diffraction analysis reveals the changes in the lattice parameter and unit cell volume of the pure perovskite tetragonal structure with space group (P4mm). Electrical analysis is carried out to investigate the dielectric properties, conductivity behaviour and dielectric loss of BaTiO3 and Ba0.995Nd0.005TiO3. Ba0.995Nd0.005TiO3 have a broaden dielectric peaks with high permittivity of 8000 and reasonably low loss tan δ which is about 0.004 (1 kHz).
      28  9
  • Publication
    The effect of cation ordering on the structure, electrical and electronic properties of cubic spinel LiNi₀.₅Mn₁.₅O₄
    ( 2025-01)
    Edi Yasa Ardiansyah
    ;
    Mohd Sobri Idris
    ;
    Rozana Aina Maulat Osman
    ;
    Fahmi Fahmi
    In this paper, we present the investigation of the impact of cation ordering on the structural, electrical, and electronic properties of a cubic spinel LiNi₀.₅Mn₁.₅O₄. Rietveld refinement using X-ray diffraction (XRD) data reveals that LiNi₀.₅Mn₁.₅O₄ annealed at 700 °C adopts a well-ordered atomic arrangement in cubic spinel (SG = P4332). Then, it is transformed to a disordered cubic spinel (SG = Fd-3m) at higher temperatures (> 800 °C). Impedance spectroscopy is employed to evaluate the dielectric and electrical properties in the temperature range of 0 to 25oC within the frequency range between 10 Hz and 100 kHz. The Cole-Cole plot indicates that grain boundaries contribute significantly to electrical conductivity and that bulk resistance decreases with increasing temperature. The AC conductivity analysis shows that the electrical conductivity of well-ordered and disordered cubic spinel LiNi₀.₅Mn₁.₅O₄ exhibits thermal activation and obeys Jonscher's universal power law. Furthermore, the electronic properties of cubic spinel LiNi₀.₅Mn₁.₅O₄ with the space groups of Fd-3m and P4332 are investigated using the density functional theory (DFT) plane-wave method. The electronic analysis of the cubic spinel LiNi₀.₅Mn₁.₅O₄ (SG = Fd-3m) indicates stronger bonding between oxygen and transition metal elements compared to the LiNi₀.₅Mn₁.₅O₄ (SG = P4332) structure. Therefore, LiNi₀.₅Mn₁.₅O₄ with the Fd-3m space group exhibits high structural stability, making it a favourable cathode material for high-voltage rechargeable lithium-ion batteries.
      16  2
  • Publication
    Dielectric and microstructural properties of BaTiO3 and Ba0.9925Er0.0075TiO3 ceramics
    ( 2017)
    Fatin Adila Ismail
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    ;
    Sanna Taking
    ;
    Zul Azhar Zahid Jamal
    BaTiO3 and Ba0.9925Er0.0075TiO3 ceramics were investigated regarding their dielectric and microstructure properties via conventional solid state reaction method. The phase pure samples were obtained when heated at 1400°C for overnight. The effect of Er3+ doped into BaTiO3 on dielectric properties and microstructural properties was investigated for composition of BaTiO3 and Ba0.9925Er0.0075TiO3. The analysis was made by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Impedance Analyzer. The XRD patterns of BaTiO3 and Ba0.9925Er0.0075TiO3 are phase pure and identical with tetragonal perovskite structure with space group of P4mm. The lattice parameters and unit cell volume of BaTiO3 increased by doping with Erbium as the crystallite size decreased. Measurements of dielectric properties were carried out as a function of temperature up to 200°C at different frequencies. Ba0.9925Er0.0075TiO3 exhibit the high value of dielectric constant (ε=6179) at Curie temperature (TC) of 120°C. SEM analysis of BaTiO3 and Ba0.9925Er0.0075TiO3 ceramics showed that the grain sizes of BaTiO3 and Ba0.9925Er0.0075TiO3 were ranged from 3.3µm-7.8µm and 2.2µm-4.7µm respectively.
      1  25
  • 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