Rozana Aina Maulat Osman
Thumbnail Image
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

Research Output

Filters

3 1
18
Reset filters

Settings
Now showing 1 - 10 of 18
No Thumbnail Available
Publication

Influence of heating temperature on structure, morphology and electrochemical performance of LiV₃O₈ cathode for lithium-ion batteries application

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.

View
No Thumbnail Available
Publication

Colossal permittivity and dielectric behaviour of (Nb₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ and (Ta₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramics

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.

View
Thumbnail Image
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.

View
No Thumbnail Available
Publication

Synthesis and physico-chemical characterization of nonlinear optical single crystals of S-carboxymethyl L-cysteine for optoelectronic devices applications

2020 , Azeezaa Varsha Mohammed , Suresh Sagadevan , Yasmin Abdul Wahab , Rozana Aina Maulat Osman

The S-carboxymethyl L-cysteine (SCLC) single crystals have been grown through slow evaporation technique. The lattice parameters of SCLC crystal have been determined using Single-crystal X-ray diffraction. From the transmission spectrum, the optical properties of the SCLC crystals have been investigated. The various functional groups of the SCLC crystal have been confirmed using the Fourier-transform infrared spectroscopy (FTIR). The mechanical properties have been studied using Vickers hardness tester. The nonlinear property is identified by Kurtz and Perry. Further, the electrical properties are studied.

View
No Thumbnail Available
Publication

Facile synthesis of layered LiV₃O₈ nanosheets and their electrochemical performance as cathode materials for Li-Ion batteries

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.

View
No Thumbnail Available
Publication

Microwave and electrical properties of SrTiO3 for DRA application

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.

View
Thumbnail Image
Publication

Fused aromatic disubstituted azomethine as organic additives in NH4SCN doped CMC based electrolyte film

2023 , Rafizah Rahamathullah , Jia Kai Low , Wan M. Khairul , Rozana Aina Maulat Osman , Mohd Ikmar Nizam Mohamad Isa

The remarkable progress of organic dye based on donor-π-acceptor concepts has been extensively studied to enhance carrier mobility, electrical performance and can perform function at an optimum level in advanced electrochemical energy devices. In this study, new organic additive for solid polymer electrolyte (SPE) has been successfully synthesized by incorporating fused aromatic azomethine (-CH=N-) dye in carboxy methylcellulose (CMC) with ammonium thiocyanate (NH4SCN) based electrolyte. Assessment of the synthesized additive has been physico-chemically characterized via Fourier transform infrared (FT-IR), UV-visible (UV-vis), 1D Nuclear Magnetic Resonance (NMR) and thermogravimetric (TGA) analysis. Besides, DFT calculation revealed that the value of HOMO-LUMO gap exhibits semiconductor properties with the activation energy of 3.135 eV. The investigation of their capability as organic additive SPE has been discovered by incorporating CMC-NH4Cl via solution-casting technique. The structural analysis was conducted to study the effect of the atomic structure in correlation towards ionic and conductivity of newly develop SPE. The ionic conductivity of SPEs system has been measured using Impedance Spectroscopy with various weight percentage (wt%) of additive. The highest conductivity of SPEs at 303K was approximately ~10-3 Scm-1 at 0.6 wt%. As a result, the incorporation of fused aromatic azomethine into the SPE has a great potential to be used for electrochemical device application.

View
No Thumbnail Available
Publication

Electrical properties of Sn doped SrTiO₃

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.

View
Thumbnail Image
Publication

Physical, electrical and optical characterizations of Ba0.5Sr0.5TiO3 (BST) thin films

2020-01-08 , Bakar Nurhanani Abu , Adnan Johari , Rozana Aina Maulat Osman , Zul Azhar Zahid Jamal , Muhammad Asri Idris , Wan Mohd Faizal Wan Nik , Man Bahari

Single layer Barium Strontium Titanate (BaxSr1-xTiO3) thin films were deposited on P type Silicon (Si) and thin Silicon Dioxide (SiO2) layer grown on Silicon (Si) substrate (1.5 cm x 1.5 cm) using spin coating technique were investigated in this work. The thin films were crystallized by annealing at 950 °C for 4 hours. Physical characterization was performed using XRD. Electrical and optical characterizations were aided by depositing Aluminum (Al) using Physical Vapor Deposition (PVD) on the thin films as electrode metal. I-V profile was obtained using Semiconductor Parametric Analyzer (SPA). A high impedance multimeter, light meter and a variable light source were introduced for optical characterizations including optical sensitivity, current density and I-V profile under variable light intensity from 0 to 900 Lux. Results show BST has diode like characteristics. The results which were compared with those from commercial solar cells and light sensors indicated that the BST thin films have potential as solar power generator and sensor.

View
Thumbnail Image
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).

View