Rozana Aina Maulat Osman
Universiti Malaysia Perlis
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Featured researches published by Rozana Aina Maulat Osman.
Advanced Materials Research | 2013
Mohd Sobri Idris; Rozana Aina Maulat Osman
This paper discussed refinement strategy that been used to reveal crystallographic properties of lithium-based complex oxides with layered rock salt structure. Rietveld analysis using XRD data was used to determine the amount of interlayer mixing and estimate oxygen contents. The structural model and refinement methodology was controlled and validated initially using a standard sample. Thus, this paper summarized structure refinement strategy that been used to quantify the degree of cation order associated with interlayer mixing and investigate the sensitivity of laboratory XRD data to oxygen non-stoichiometry that recently published elsewhere [.
Advanced Materials Research | 2013
Rozana Aina Maulat Osman; Mohd Sobri Idris
Fresnoite with composition Ba2TiSi2O8 (B2TS2) was first found in 1965, adopting a non-centrosymmetric structure. It also reported to crystallize in a tetragonal unit cell with a=8.52Å and c=5.210Å leading to some possible application as hydrophone, transducer and second harmonic generation and low temperature co-fired ceramics (LTCC). B2TS2 were synthesized by conventional solid state reaction. Phase pure B2TS2 was obtained after heating the pellets at a final sintering temperature of 1230 °C in air at 92 h. Study found that Fresnoite B2TS2 is a type of materials which are not ferroelectric and instead show perfect dielectric insulator behaviour with resistance >106Ωcm at temperatures below 750°C and also shows nonideal debye respone. The activation energy for conduction of B2TS2 samples is very high, indicating that these materials are highly insulating.
international conference functional materials and metallurgy | 2016
Fatin Adila Ismail; Rozana Aina Maulat Osman; Mohd Sobri Idris
Rare earth doped Barium Titanate (BaTiO3) were studied due to high permittivity, excellent electrical properties and have wide usage in various applications. This paper reviewed on the electrical properties of RE doped BaTiO3 (RE: Lanthanum (La), Erbium (Er), Samarium (Sm), Neodymium (Nd), Cerium (Ce)), processing method, phase transition occurred and solid solution range for complete study. Most of the RE doped BaTiO3 downshifted the Curie temperature (TC). Transition temperature also known as Curie temperature, TC where the ceramics had a transition from ferroelectric to a paraelectric phase. In this review, the dielectric constant of La-doped BaTiO3, Er-doped BaTiO3, Sm-doped BaTiO3, Nd-doped BaTiO3 and Ce-doped BaTiO3 had been proved to increase and the transition temperature or also known as TC also lowered down to room temperature as for all the RE doped BaTiO3 except for Er-doped BaTiO3.
international conference functional materials and metallurgy | 2016
T. A. T. Sulong; Rozana Aina Maulat Osman; Mohd Sobri Idris
Rapid development of a modern microwave communication system requires a high quality microwave dielectric ceramic material to be used as mobile and satellite communication. High permittivity of dielectric ceramics leads to fabrication of compact device for electronic components. Dielectric ceramics which used for microwave applications required three important parameters such as high or appropriate permittivity (er), high quality factor (Q f ≥ 5000GH z) and good temperature coefficient of resonant frequency (τf). This paper review of various dielectric ceramic materials used as microwave dielectric materials and related parameters for antenna applications.
international conference functional materials and metallurgy | 2016
Nurhamidah Zakaria; Rozana Aina Maulat Osman; Mohd Sobri Idris
Ba0.5Sr0.5Co0.8Fe0.2O3-δ was successfully prepared using modified solid-state synthesis routes. The lowest temperature to obtained single phase of Ba0.5Sr0.5Co0.8Fe0.2O3-δ is about 900°C for 15 hours. Longer period of time are required compared to only 5 hours at 950°C as established in literatures. The X-ray Diffraction (XRD) data confirmed that Ba0.5Sr0.5Co0.8Fe0.2O3-δ is formed a cubic perovskite with the space group of Pm-3m. The lattice parameters of Ba0.5Sr0.5Co0.8Fe0.2O3-δ are a = 3.990 (1) A and unit cell volume is V = 63.5 (1) A3. The Rietveld refinement of XRD data revealed that the crystal structure of Ba0.5Sr0.5Co0.8Fe0.2O3-δ slightly changes as a function of temperature.
Advanced Materials Research | 2013
Mohd Sobri Idris; Rozana Aina Maulat Osman
The effect of preparation conditions, temperature and atmosphere, on oxygen stoichiometry and interlayer cation mixing in the layered rock salt material LiNi0.8Mn0.1Co0.1O2-δ has been investigated using X-Ray powder diffraction, including Rietveld refinement. Interlayer mixing occurs as a direct consequence of oxygen deficiency; samples with least oxygen deficiency and most cation order were obtained on firing in O2 at ~ 900 950C.
international conference functional materials and metallurgy | 2015
S.P. Soo; Idris; Rozana Aina Maulat Osman; A. Rahmat
The interlayer mixing of layered rock salt cathode materials LiNi0.7Mn0.1Co0.2O2 that prepared by mixed hydroxide method at various temperatures (750-950°C) has been studied. X-ray Diffraction (XRD) was used to determine a suitable temperature range to obtain the fully reacted sample. Phase of pure sample was obtained at high temperature above 850°C. The results of XRD show that the LiNi0.7Mn0.1Co0.2O2 samples are iso-structural with α-NaFeO2 with space group of R-3m.The sample that heated at 900°C exhibits a well-ordered and lower cation mixed layered structure than others. Rietveld refinement using XRD data was used to determine the amount of interlayer mixing vary as a function of temperature. Refinements data showed that the interlayer mixing varies depend upon the synthesis temperature and the optimum temperature to prepare LiNi0.7Mn0.1Co0.2O2 with the lowest amount of interlayer mixing was 900°C.
international conference functional materials and metallurgy | 2015
N.A. Shafiqa; Idris; C.A. Salmie Suhana; Rozana Aina Maulat Osman; Tze Qing Tan
Synthesis of LaYO3 was carried out via conventional solid state reaction method. The polycrystalline samples were sintered at temperatures in the range of 1300 °C to 1500 °C with each deviation is 50 °C. X-ray diffraction (XRD) analysis indicated that the perovskite ceramic obtained its single phase at 1500 °C with ordered monoclinic perovskite structure. The pure phase sample showed 98.79 % relative density and scanning electron micrographs also proved that the porosity of the sample reduced when sample undergo sintering.
Applied Mechanics and Materials | 2015
Nur Farahin Abdul Hamid; Rozana Aina Maulat Osman; Mohd Sobri Idris
Undoped barium titanate and lanthanum (La) doped barium titanate (BaTiO3) were studied for ferroelectric properties with the formula of Ba1-xLaxTi1-x/4O3 for x=0.1 and being prepared by using conventional solid state method reaction. The pure phase of this composition which x=0 were found at final heating temperatures starting from 1300°C and x=0.1 at 1350°C for overnight in air with intermittent grinding. The changes in the crystal structure of the composition were detected by using X-ray diffraction. Impedance Spectroscopy analysis is carried out to determine the dielectric properties for undoped BaTiO3 and La doped BaTiO3 for x=0.1.
Applied Mechanics and Materials | 2015
Y.M. Chin; Rozana Aina Maulat Osman; Mohd Sobri Idris
The layered rock salt LiNi0.7Mn0.3O2 was prepared by conventional solid-state synthesis route. The prepared samples were analysed using X-ray diffraction (XRD) to determine purity of samples. Then, structural analysis and crystallographic properties of samples were analysed using Rietveld refinement. Rietveld refinement results indicated that the amount of cation disorder in the layered rock salt structure highly influenced by temperature and synthesis conditions. The most optimum temperature to obtain the highest degree of cation ordering is between 850oC and 900oC in air.