Papers by Author: Nur Amanina Mat Jan

Abstract: Series of glass samples with composition (72.5-x)TeO₂-15MgO-10Na₂O-2.5Nd₂O₃-xNiO where 1.0 ≤ x ≤ 2.5 mol% are prepared using melt quenching method. The glasses are characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD spectra confirmed the amorphous nature of prepared glasses. TEM images manifest the existence of NiO NPs which are homogeneously distributed in the glass matrix. The magnetization M(H) curve reveals that the glass displays an anomalous hysteresis behavior at room temperature. It is observed that M(H) is dependent on the NiO content. The initial curve of magnetization lies positively as a function of the magnetic field under 1000 H (O.e).

Abstract: Modifying the optical and structural properties of tellurite glasses by controlling rare earth doping is an important issue. Neodymium doped magnesium-tellurite glasses of composition TeO₂-MgO-Na₂O with concentration from 0.5 to 2.5 mol% were synthesized by conventional melt-quenching technique. The amorphous natures of the glass were confirmed from x-ray diffraction (XRD) pattern. The absorption spectra (exhibits five bands) were recorded to determine the optical energy gap and Urbach energy. The values of the optical band gap are found to lie between 3.04-3.20 eV, while the Urbach energy values varies are between 0.21-0.12 eV. The optical energy gap for indirect forbidden transition has increased whereas the values of Urbach energy have decreased with the increasing of Nd₂O₃ content. The structural and optical properties were found to be strongly affected by the varying concentration of Nd³⁺ ions.

Abstract: Series of glasses based on (75-x)TeO₂-15MgO-10Na₂O-xNd₂O₃, where x=0, 1.0, 2.0 and 3.0, are synthesized by conventional melt-quenching technique. The nanoglass particles are derived from heat treatment of this glass near crystallisation temperature for 3 hours. The existence of nanocrystalline nature of this glass is confirmed by x-ray diffraction (XRD) technique followed by calculation using Scherrer equation. Meanwhile, the crystallization temperature, Tc determined using Differential thermal analysis (DTA). The fluorescence spectra of Nd³⁺ ions exhibit emission transition of ²P_3/2⁴I_9/2, ⁴G_7/2⁴I_9/2, ²H_11/2⁴I_9/2, and ⁴F_9/2⁴I_9/2 under 765 nm excitation wavelengths.

Abstract: . The study of the crystallization kinetics of rare-earth doped glass stimulated much interest especially for crystallization process. In this work transparent Eu2O3 doped glasses with composition TeO2 - Na2O – MgO were prepared using conventional melt-quenching technique. The amorphous nature of glass was confirmed using X-ray diffraction method. The influence of Eu3+ content on the crystallization kinetics of the glass such as activation energy (Ea) was thoroughly evaluated under non-isothermal conditions using DTA. The crystallization kinetic at different heating rate from 5 °C min-1 to 25 °C min-1 at different crystallization temperature (Tp) were examined and verified using Ozawa method. The result showed that the activation energy (Ea) was decreased with the increasing of the dopant concentration from 319.8 eV to 93.5 eV.

Abstract: A series of Antimony Borate glass samples were investigated to determine the structural feature. The glass samples from the series of xSb2O3:(1-x)B2O3 with composition of 20≤x≤60 mol% and 0.6 Sb2O3:0.4B2O3:y with y is 0.01 mol% of Nb2O5, CuO, ZnO system have been prepared using melt-quenching technique. The structural properties of Sb2O3 host and the introduction of dopents onto the host sample has been investigated using Infrared and RAMAN Spectroscopy. The result of IR and Raman Spectroscopy revealed that the network structure of the studied glasses is mainly based on BO3 and BO4 units placed in different structural groups, the BO3 units being dominant. IR spectra obtained shows conversion of BO3 to BO4 units upon the introduction of Sb2O3 commonly known as boron anomaly effect. The glass network can be modified with the presence of Sb2O3 and activator ions. The significant behavior in Raman Spectra indicates the presence of boroxol groups consisting of pure BO3 groups and mixed BO3-BO4 structural units. This study shows that the vibrational spectroscopy (Infrared and Raman) provide useful method, and inter-complementary information about the structural properties of antimony modified borate glasses.