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Abstrak :
Data XRD dari nanokomposit Ti-Si-N telah dianalisis menggunakan program GSAS berbasis metode Rietveld untuk mengidentifikasa fasa-fasa pembentuk serta komposisinya dan mencari pengaruhnya terhadap kekerasan material tersebut. Telah ditemukan fasa-fasa baru dalam sampel tersebut, disamping fasa-fasa nanokomposit nc-TiN/a-Si3N4 & a-/nc-TiSi2 yang telah banyak dikenal. Dari fasa-fasa kristal yang diperoleh, setelah dilakukan perhitungan fraksi fasa amorf Si3N4 dan TiSi2 maka diperoleh bahwa kekerasan optimal terjadi pada kandungan a-Si3N4 8 wt.%.

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Phase composition analysis using rietveld methode and it?s influence to the hardness of Ti-Si-N nanocomposites. XRD data of nanocomposites Ti-Si-N have been analysed using GSAS based on Rietveld Method in order to identify phases and their composition as well as its influence on the hardness of these nanocomposites. Several new phases have been found in the sample beside the nc-TiN/a-Si3N4& a-/nc-TiSi2 that have been known widely. From the obtained crystalline phase, after the calculation of amorf Si3N4 and TiSi2 phase fraction, it is found that the optimum hardness can be reached when the fraction of a-Si3N4 phase around 8 wt.%.

Abstrak :
Analisis Rielveld dengan program EXPGUI-GSAS dapat digunakan untuk meneliti kekristalan material. Pada penelitian dilakukan penghalusan parameter-parameier struktur liga sampel film tipis PIZT diatas subslrat Pi (200)/Si(VSi(tOO) dengan variasi doping indium, didapat indikator keberhasilan R-pola (Rp) pada selang (5,77-10,36)%, R-pola dengan pemberat (wRp) pada selang aniara (8,59-15,35)% dan Goodness of fit (GoF) pada selang antara 1,036-5,462. Indikator yang didapal secara fisik dapat ditandai dengan miripnya kurva kalkulasi dengan kurva eksperimen. Semua sampel PIZT substrat Pt menunjukkan sistem kristal kubik dengan grup ruang Fm3m. Selain itu didapat nilai parameier kisi hasil penghalusan yang mendekati nilai pada international Centre for Diffraction Data (ICDD).

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We have use Rietveld analysis on EXPGUI-GSAS plalform to examine the crystalinity of PIZT on Pt Substrate. In this experiment, we have used 3 samples of PIZT thin film in the platinum substrate with variation on the percentage of indium doping. The value of efficacy indicator for 3 specimens included R-Pattern (Rp) between (5,77-10,36)%, weighted of R-Pattern ( wRp) between ( 8,59-15.35)% and Goodness of Fit (GoF) between 1,036-5,462. The value of efficacy indicator marked physically as alike between the calculated curve and experiment curve. Most of the sample of PIZT thin films in platinum substrate show that the crystal structure are cubic with space group Fm3m and lallice parameter near the value on the Powder Diffraction Data-International Center for Diffraction Data.

Abstrak :
(Ba0.5Sr0.5)1-xCuxTiO3 telah dihasilkan dari Ba0.5Sr0.5TiO3 (BST) yang doping Cu (x=1%, 2%, 4%) dengan metode Chemical Solution Deposition (CSD) dan proses spin coating (3000 rpm, selama 30 detik), di atas permukaan substrat Si (1 0 0) dan Pt/TiO2/SiO2/Si (2 0 0). Proses thermal hydrolisis, pyrolisis dilanjutkan dengan annealing pada suhu 8000C untuk pembentukan kristal. Hasil karakterisasi XRD dengan penghalusan GSAS, doping Cu (1%, 2% dan 4%) sudah masuk dalam BST menjadi kristal (Ba0.5Sr0.5)1-xCuxTiO3 dan menyebabkan perubahan jarak antar kisi dari kristal. Analisa struktur, mikrostruktur, morfologi dan topografi lapisan (Ba0.5Sr0.5)1-xCuxTiO3 berpengaruh terhadap hasil karakterisasi sifat listrik (polarisasi dan konstanta dielektrik). Polarisasi (spontan dan remanen) untuk BST murni lebih besar dibandingkan dengan BST yang di-doping Cu, tetapi doping Cu memperkecil medan koersif lapisan. Penggunaan substrat Pt/TiO2/SiO2/Si untuk penumbuhan lapisan (Ba0.5Sr0.5)1-xCuxTiO3, dapat memperkecil medan koersif dibandingkan dengan substrat Si. Telah dihasilkan konstan dielektrik dari lapisan (Ba0.5Sr0.5)1-xCuxTiO3 sebesar 900. Karakterisitik dielektrik dan medan koersif yang rendah dari penumbuhan lapisan BST diatas permukaan substrat, sangat baik untuk switching pada aplikasi memori ferroelektrik. ......(Ba0.5Sr0.5)1-xCuxTiO3 fabricated from Ba0.5Sr0.5TiO3 (BST) with doping Cu (x=1%, 2%, 4%) used Chemical Solution Deposition (CSD) method and spin coating (3000 rpm, 30 second) process, on substrate Si (1 0 0) and Pt/TiO2/SiO2/Si (2 0 0). The Thermal process, hydrolisis, pyrolisis and annealing at temperature 8000C for crystallization. Characterization used XRD with refinement GSAS, doping Cu (1%, 2% dan 4%) doped in BST became crystal (Ba0.5Sr0.5)1-xCuxTiO3 and changed lattice parameter of crystal. The structure, microstructure, morphology and topography of film (Ba0.5Sr0.5)1-xCuxTiO3 were analyzed and correlated to electronic properties of film (Polarization and Dielectric). The undoped BST had more high polarization (spontant and remanent) than BST with doping Cu, but doping Cu made decrease coersive field of film. The used substrate Pt/TiO2/SiO2/Si for growthing of film (Ba0.5Sr0.5)1-xCuxTiO3, could more decrease coersive field than used substrate Si. The dielectric constant of film (Ba0.5Sr0.5)1-xCuxTiO3 are 900. The dielectric properties, low coersive field of growth BST films on substrate propose for utilization in switching ferroelectric memory.

Abstrak :
One basic problematic aspect in x-ray diffraction phase analysis is microabsorption effect which may arise from the size of the crystallite phases. Complication of the problem may intensify in sintered ceramic materials where milling of the samples is not simple. We report the Rietveld x-ray diffraction phase analysis of MgO-􀁡-Al2O3 powder mixtures with phase content ratio of 1:1 by weight and MgO-Y2O3 sintered ceramic composites with Y2O3 contents of 10%, 20% and 30% by weight. The mixtures were pre-sintered at 1000􀂰C for 2 hours and then milled while the composites were sintered at 1550􀂰C for 3 hours. The phase composition analysis was done using Rietica, a non-commercial Rietveld method-based software. Relative and absolute phase compositions were examined and results showed that there was a significant amount of phase composition bias resulted from the examination. For the powder mixture, milling can reduce microabsorption effect and hence the calculation bias. For the ceramic composite where milling is almost impossible, additional of Y2O3 caused smaller crystallite size of MgO, so that composition bias is smaller in composites with higher Y2O3 content. A mathematical model is proposed to provide more acceptable phase composition results.

Abstrak :
Pada penelitian ini, mullite yang disintesis dari aluminum nitrat hidrat [(Al(NO3)3.9H2O] dan sol silika sekam padi dikenakan pada perlakuan sintering dengan suhu 900, 1000, 1100, 1200, dan 1300°C, kemudian dikarakterisasi dengan difraksi sinar-x (XRD) dilanjutkan dengan penghalusan menggunakan metode Rietveld, dan analisis termal diferensial (DTA). Hasil penelitian menunjukkan bahwa dalam sampel yang disintering pada suhu 900°C, tidak ditemukan fasa mullite, tetapi fasa kristobalit dan alumina terdeteksi dengan jelas. Pembentukan mullite baru terjadi pada suhu 1000°C dan bertumbuh dengan peningkatan suhu ditandai dengan kenaikan persen berat (wt%) dari 62,62 menjadi 92,29%, disertai penurunan persen berat kristobalit dari 22,42 menjadi 1,25% dan penurunan persen berat alumina dari 77,58 menjadi 6,46%. Hasil penghalusan menunjukkan korelasi yang baik antara unit sel hasil perhitungan dan hasil pengamatan, dengan dimensi unit sel adalah a = 7,545 nm, b = 7,689 nm dan c = 2,884 nm untuk mullite, a = b = 0,5531 nm, dan c = 0,6923 nm untuk kristobalit, dan a = b = 0,5026 nm, dan c = 1,2808 nm untuk alumina. Hasil analisis dengan DTA menunjukkan bahwa dalam sampel yang tidak disintering, hanya terdapat alumina dan silika, sementara dalam sampel yang disintering terdapat mullite, alumina, dan kristobalit.

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In this study, mullite synthesized from aluminum nitrate hydrate [(Al(NO3)3.9H2O] and silica sol from rice husk was subjected to sintering treatment at temperatures of 900, 1000, 1100, 1200, and 1300°C, and characterized using x-ray diffraction (XRD), followed by Rietveld refinement, and differential thermal analysis (DTA). The results indicated that in the sample sintered at 900°C, no mullite phase was identified, but crystoballite and alumina were well detected. The formation of mullite started at temperature of 1000°C and continued to grow at higher temperatures, resulted in increased weight percentage (wt%) from 62.62 to 92.29%, while crystoballite and alumina decreased from 22.42 to 1.25% and from 77.58 to 6.46 % respectively. A good correlation was found between the calculated and observed unit cells. For mullite phase, the unit cell dimensions are a = 7.545 nm, b =.689 nm and c = 2.884 nm, for crystoballite a =b = 0.5531 nm and c = 0.6923 nm, and for alumina a = b = 0.5026 nm, and c = 1.2808 nm. The DTA analyses revealed that in the untreated sample, only alumina and silica were detected, while in the sintered samples we found the existence of mullite, alumina, and crystoballite.

Abstrak :
Sampel Nd2Fe14B yang berupa bubuk dan berwama hitam telah diperiksa dengan difraksi sinar-x pada temperatur 299,7 K. Data hasil difraksi sinar-x tersebut dianalisis dengan analisis Rietveld untuk memperhalus parameter-parameter mikronya. Sebanyak 25 parameter telah diperhalus, yaitu: koordinat atom (12), koefisien puncak FWHM (3), konstanta kisi (2), faktor skala (I), titik nol (1), latar belakang (4), orientasi yang disukai (1) dan bentuk puncak (1). Struktur kristal Nd2Fe14B adalah tetragonal (grup ruang P42/mnm) dengan konstanta kisi a = b = 8,782 Ǻ , dan c = 12,146 Ǻ , orientasi yang disukai pada bidang refleksi (331) di 2θ = 52°. Dengan koordinat atom hasil penghalusan tersebut dicari jarak rata-rata atom tetangga terdekat (rave) setiap posisi, hasil tersebut digunakan untuk menghitung momen magnetik lokal (mi), diperoleh m Nd(4f) = 1,81 µB, m Nd(4g) = 2,79 µB, m Fe(16k1)=1,89 µB, m Fe(16k2) = 2,03 µB, m Fe(8j1)= 1,87 µB, m Fe(8j2) = 2,34 µB, m Fe(4e)=1,87 dan m Fe(4c)=1,64 µB, Sedangkan besaran intrinsik energi maksimum (BH)max adalah 64,18 MGOe atau 510,87 kJ/m3.

Abstrak :
Composited tile was made using marble particles, phenol resin and hcxamethy leneleiramine (HEXA) as the catalyst. The matrix and hardener of these materials were mixed on volume variation from 62.50 ml to 12?,()<) ml. and on variation of 25. 40 and 60 mesh. Samples were dried in a room temperature for 3 hours. The compressive strength and crystal structure were analysed. The results showed that compressive strength values were in range of 6.15 x I07 N/m" - 9.61 x Id7 N/n. and there were two crystal structures consisted of marble crystal and phenol crystal. The analysis was carried out by using the Rietveld semi quantitative analysis. The final crystal structure of marble is rhombothedral, where the lanice constants arc a h =- 4.969 A: c = 17.026 A. This results indicate that the composites and marble can he used to make tile, because they were lighter, stronger and the amount of crystals increases compared with the pure marble.

Abstrak :
This research presents the use of the Rietveld method to study the phase composition of cordierite (MG2AL4SI5O18) ceramics prepared from rice husk silica, after the samples were sintered at 1300, 1400 and 1500 °C. The formation of cordierite is temperature-dependent as indicated by the relative phase composition obtained from x-ray diffraction patterns for the cordierite and spinel increased markedly with increasing temperature, i.e, from 38.98 to 54.15 wt% and from 11.81 to 17.99 wt % following the increase in temperature from 1300-1500 °C, respectively. The above values were obtained with the aid of the Rietveld method, carried out until the goodness of fit values (GoF) reached below 2, which is considered a satisfactory value to reveal the real phase composition. Different plots produced by refinement using the Rietveld method also reveal a reasonable fit between the observed and the calculated plot, demonstrating the usefulness of the method for calculating the quantity of phase composition in the sintering process.

Abstrak :
PZT (PbZr1-xTixO3) merupakan bahan berbentuk kristal perovskite yang dapat dimanfaatkan sebagai sensor inframerah. Penambahan sedikit dopan (bahan pendoping) dapat mengubah secara drastis karakteristik spesifik dari bahan keramik-ferroelektrik seperti polarisasi spontan, sifat dielektrik, sifat elektromekanik, elektrooptik dan sifat lainnya. Hard doping dengan menggunakan ion In3+ diaplikasikan pada penelitian ini dan dilakukan penumbuhan lapisan tipis dari bubuk PIZT (PbInxZryTi1-x-yO3-x/2) pada substrat Si(100) dengan metode Chemical Solution Deposition (CSD) dengan konsentrasi 0,5 M dan kecepatan putar spin coating 3000 rpm. Karakteristik bahan PIZT baik bubuk maupun lapisan tipisnya diuji dengan difraksi sinar x. Analisis Rietveld dilakukan dengan menggunakan program GSAS-EXPGUI dan diperoleh parameter kisi dan komposisi fasa dari kristal. Polarisasi spontan (Ps) PIZT bubuk dan lapisan tipisnya mengalami penurunan dibandingkan dengan bahan asalnya (PZT). Polarisasi spontan yang optimum dari lapisan tipis PIZT dicapai pada rentang doping 0,5% - 1% In2O3. Momen quadrupol potensial listrik (�?�Q(r)) bahan PIZT pada suatu titik P (0,0,2a) mencapai kondisi optimum pada % doping 6% In2O3 dan dari hasil penelitian ini juga menunjukkan bentuk lapisan tipis PIZT memiliki nilai (�?�Q(r)) yang lebih baik daripada bentuk bubuknya untuk rentang doping > 1% In2O3.

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The Calculation Spontaneous Polarization and Quadrupole Moment of Electric Potential PIZT (PbInxZryTi1-x-yO3-x/2). PZT (PbZr1-xTixO3) is a perovskite crystal that can be used for IR sensor. Small amount of dopant can drastically change the specific characteristic of ferroelectric ceramic such as spontaneous polarization, dielectric constant, electromechanical and also electro-optic properties. The addition of In3+ ion (called as hard doping) has been applied in this research. Thin film of PIZT (PbInxZryTi1-x-yO3-x/2) has been deposited on Si(100) substrate with Chemical Solution Deposition (CSD) method. The concentration of solution is 0,5 M and the angular speed applied of spin coating is 3000 rpm. The PIZT sample has been analyzed with x-ray diffraction method. Rietveld analyses using GSAS-EXPGUI software resulted lattice parameter of crystal and phase compositions of PIZT samples. The values of all sample PIZT spontaneous polarization (Ps) have been calculated lower than PZT. The optimally Ps was reached at 0,5% to 1% In2O3 doping. Quadrupole moment of electric potential (�?�Q(r)) at point P (0,0,2a) reached optimum at 6% In2O3 doping and they also showed that PIZT thin film have �?�Q(r) higher value than their bulk form for In2O3 doping >1%.