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Engkir Sukirman
Pusat Sains dan Teknologi Bahan Maju - BATAN Kawasan Puspiptek, Serpong, Tangerang Selatan, 15314
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

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PENINGKATAN FLUX PINNING PADA BULK SUPERKONDUKTOR YBa2Cu3O7-X MELALUI PROSES MELT TEXTURE GROWTH Adi, Wisnu Ari; Sukirman, Engkir; Winatapura, Didin S.; Sulungbudi, Grace Tj.
Jurnal Sains Materi Indonesia Vol 3, No 1: OKTOBER 2001
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1168.137 KB) | DOI: 10.17146/jusami.2001.3.1.5257

Abstract

PENINGKATAN FLUX PINNING PADA BULK SUPERKONDUKTOR YBa2Cu3O7-X MELALUI PROSES MELT TEXTURE GROWTH. Keberadaan medan magnet luar H terhadap bahan superkonduktor mengakibatkan timbulnya pergerakan vortex yang menyebabkan timbulnya energi yang sangat disipatif. Sehingga bahan memiliki rapat arus kritis (Jc) yang cukup rendah. Untuk itu diperlukan flux pinning yang diharapkan dapat menahan gerakan vortex tersebut. Pada penelitian ini dipelajari adanya peningkatan flux pinning pada sampel superkonduktor sistem YBa2Cu3O7-X dari proses sintering (YBCO-sintering) menuju proses melt texture growth ( YBCO-MTG). Besarnya rapat gaya pinning (Fp) ini dipengaruhi oleh inhomogenity bahan yang berupa batas butir, impuritas bahan yaitu YBCO fasa-211, rendahnya suhu eksperimen, dan tingginya medan magnet luar H. Fp maksimum untuk sampel YBCO—sintering dan YBCO-MTG berturut-turut adalah 1,42 x 108 Nm-3 (H = 17 kOe) dan 7,39 x 109 Nm-3 (H = 14 kOe) yang diukur pada suhu T = 5 K. Jc maksimum untuk sampel YBCO- sintering dan YBCO-MTG berturut-turut adalah 1,78 x 104 A.cm-2 dan 5,76 x 104 A.cm-2. Pada Fp yang optimum didapatkan Jc yang maksimum. Dengan mengontrol dan mengoptimalkan Fp diharapkan dapat meningkatkan Jc yang lebih tinggi.
Analysis on the Crystal Structure of the Piezoelectric Nanocrystal Ceramic of Pr-doped Bi1/2Na1/2TiO3 using Molten-Salt Synthesis Ahda, Syahfandi; Ambarwati, Vita; Mardiyanto, Mardiyanto; Sukirman, Engkir; Sugeng, Bambang
Makara Journal of Science Vol. 25, No. 3
Publisher : UI Scholars Hub

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Abstract

One of the future technologies in nuclear reactors is the ability of piezoelectric materials to monitor reactor cores as sensors. Particularly, Pb-free piezoelectric materials, such as Bi1/2Na1/2TiO3, have been examined to improve the ability of their piezoelectric properties. In this study, we attempted to add Pr6O11 dopant material with mole ratios of 0, 0.3, 0.5, and 0.7 mol%. The synthesis process used in this study is the molten-salt synthesis method with a NaCl and KCl salt mole ratio of 1:1. The crystal structure analysis using the refinement process of the Rietveld method of the HighScore software was performed. Accordingly, a rhombohedral crystal structure system with lattice parameters of 3.8809(2), 3.8831(2), 3.8834(7), and 3.8816(2) angstroms and variations in the content of Pr6O11 was obtained. The optimal lattice parameter was discovered with the addition of 0.5 mol% of Pr6O11. The morphology of the synthesis product is still unclear for each addition of dopant material due to the large number of granular agglomerations.
Neutron Diffraction Study of Multiferroic 0.6NiFe2O4/0.4BaTiO3 Composite Sukirman, Engkir; Sarwanto, Yosef; Ahda, Syahfandi; Insani, Andon
Makara Journal of Technology Vol. 23, No. 3
Publisher : UI Scholars Hub

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Abstract

Neutron diffraction study on the 0.6NiFe2O4/0.4BaTiO3 multiferroic composite has been carried out. The 0.6NiFe2O4/0.4BaTiO3 multiferroic composites have been synthesized by solid reaction method. In this study, 20 g of BaTiO3 (BTO) and 20 g of NiFe2O4 (NFO) compounds were prepared from the powder raw materials of BaO3 and TiO2 for BTO, and NiO and Fe2O3 for NFO. Furthermore, both BTO and NFO were each crushed for 5 hours using High Energy Milling (HEM). Then the BTO and NFO were calcined in the furnace at 950 °C/5 hours and 900 °C/5 hours, respectively. Both NFO and BTO precursors were manually mixed with a weight percent ratio of NFO:BTO was 100:0, 60:40, and 0:100, hereinafter referred to NFO, NFO/BTO, and BTO, respectively. Then the three samples were pressed into pellets. The pellets were then sintered at 1150 °C/5 hours with a heating rate of about 44.8 °C/min. Once cooled to room temperature within the furnace it was obtained NFO, BTO, and NFO/BTO multiferroic composite. The magnetic properties of the material were observed with the aid of the Vibrating Sample Magnetometer (VSM) instrument. The nuclear structure of BTO, and the magnetic structure of NFO, and NFO/BTO multiferroic composite were determined by neutron diffraction technique using the high resolution powder neutron diffractometer. The cations arrangement of NFO was obtained by whole pattern fitting with the Rietveld method based on neutron diffraction data using FullProf software. The cations arrangement was obtained by refining the occupancy of individual cation at tetrahedral and octa-hedral sites. The results of the analysis show that both NFO and 0.6NFO/0.4BTO samples have a mixed spinel structure, it means that there are cations of Ni2+ and Fe3+ on A-site and B-site. In NFO sample, the cations distribution among the A-site and B-site of NiFe2O4 is [Ni0.002Fe0.852][Ni0.006Fe0.862]2O4. The cations distribution among the A-site and B-site of NiFe2O4 in 0.6NFO/0.4BTO samples is [Ni0.0250Fe0.8975] [Ni0.012Fe0.950]2O4. So, the effect of adding BTO as a composite is to increase Ni2+ occupancy by 12.5 times on A-site and 2 times on B-site. The magnetic moment of mul-tiferroic 0.6NFO/0.4BTO composite is 2.4(5) μB same as one of NFO. The BTO content in the composite has caused ten-sile strains induced into the NFO lattice, and at the same time, tensile strains of NFO caused the compressive strain on the c lattice of BTO even though the unit cell volume of BTO is also increasing from 64.100(5) to 64.374(6) Å3.
Synthesis and Characterization of LaF3:Ce Scintillator Material Sukirman, Engkir; Purwamargapratala, Yustinus; Sugeng, Bambang; Wahyudianingsih, Wahyudianingsih; Gunawan, Indra; Ahda, Syahfandi; Sudjatno, Agus; Dimyati, Arbi
Jurnal Sains Materi Indonesia Vol. 25 No. 1 (2023): Jurnal Sains dan Materi Indonesia
Publisher : BRIN Publishing (Penerbit BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/jsmi.2023.185

Abstract

Synthesis and Characterization of LaF3:Ce Scintillator Material.Synthesis and characterization of the LaF3:Ce scintillator have been carried out. Synthesis was carried out using the co-precipitation method. In this study, the raw materials used were NaF, LaCl3•7H2O, and Ce(NO3)3•6H2O with ethanol and distilled water as a solvent; while surfactants were used oleic acid. In this study, the compound LaF3:0.2Ce was synthesized. The sample was characterized by using an X-Ray Diffractometer (XRD), a Scanning Electron Microscope (SEM), and a Spectrofluorometer. The analyzed data showed that the 82.6 weight fraction of LaF3:0.2Ce phase has precipitated accompanied by the formation of NaCl and C2Ce phases of 5.1 and 12.3 weight fraction, respectively. The NaCl phase is a by-product of the chemical reaction: xLaCl3•7H2O + zCeCl3•7H2O + 3NaF → LaxCezF3 + 3NaCl + 7H2O which could be removed from the precipitate solution by an appropriate separation method, while the C2Ce one appeared as a result of heating the sample at 400ºC. The LaF3:Ce scintillator sample shows the phenomenon of a bluish glow with a lifetime, t = 6 × 10-10 seconds even in the presence of a foreign phase. The existence of NaCl and C2Ce as a local environment still makes LaF3:0.2Ce has normal lifetime characteristics.
Co-Authors Ambarwati, Vita Andon Insani Arbi Dimyati Bambang Sugeng Didin S. Winatapura Grace Tj. Sulungbudi Indra Gunawan Mardiyanto Mardiyanto Sudjatno, Agus Syahfandi Ahda Wahyudianingsih, Wahyudianingsih Wisnu Ari Adi Yosef Sarwanto Yustinus Purwamargapratala