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https://ptsldigital.ukm.my/jspui/handle/123456789/499579Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Roslan Abd Sukor, Prof. Dato' Dr. | - |
| dc.contributor.author | Ali Agail Hamed Abdulgader (P50310) | - |
| dc.date.accessioned | 2023-10-13T09:32:55Z | - |
| dc.date.available | 2023-10-13T09:32:55Z | - |
| dc.date.issued | 2014-04-30 | - |
| dc.identifier.other | ukmvital:80170 | - |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/499579 | - |
| dc.description | Ketumpatan arus genting superconductor suhu tinggi menurun dengan cepat apabila dikenakan medan magnet kerana humungan lemah Antara butiran dan pengepinan yang lemah. Kesan penambahan nano zarah ZnO, NiO dan SnO2 dengan saiz berlainan terhadap sifat superkonduktor Bi1.6Pb0.4Sr2Ca2Cu3O10 dalam bentuk pukal dan pita telah dikaji dengan teknik pembelauan sinar-X (XRD), pengukuran rintangan elektrik penduga dan mikroskop elektron imbasan (SEM). Teknik sepemendakan digunakan untuk menyediakan serbuk superkonduktor Bi1.6Pb0.4Sr2Ca2Cu3O10 (Bi2223). Dua saiz purata NiO (8 dan 16 nm), ZnO (6 dan 30 nm) dan SnO2 (8 dan 48 nm) dengan komposisi 0.00 ke 0.05 % berat telah ditambah ke dalam serbuk superkonduktor Bi1.6Pb0.4Sr2Ca2Cu3O10-(MO)x (M=Ni, Zn, Sn) dan disinter dalam udara selama 48 jam pada suhu 850 °C. Suhu genting (Tc(R=0)) iaitu 101 K bagi sampel tulen didapati menurun dengan penambahan NiO dan SnO2 disebabkan oleh penurunan pecahan isipadu fasa Bi2223. Bagi sampel yang ditambah ZnO, Tc(R=0) meningkat dengan penambahan ZnO sehingga 0.02 % berat dan menurun dengan penambahan yang seterusnya. Semua sampel dengan NiO dan ZnO menunjukkan suhu genting mula (Tc-mula) kira-kira 112 K dan 106-110 K untuk sampel di tambah SnO2. Analisis pembelauan sinar-X menunjukkan kebanyakan puncak pembelauan adalah fasa Bi2223 dengan kehadiran puncak Bi2212 yang berkeamatan rendah. Ketumpatan arus genting (Jc) bagi sampel tulen adalah 21 mA/cm2 pada suhu 77 K. Ketumpatan arus genting bagi semua sampel dengan penambahan zarah bersaiz nanometer adalah lebih tinggi daripada sampel tulen. Semua sampel dengan penambahan zarah bersaiz nanometer menunjukkan butiran yang lebih kecil berbanding dengan sampel tulen. Pita Bi1.6Pb0.4Sr2Ca2Cu3O10 telah disediakan berdasarkan keputusan Jc tertinggi sampel pukal. Dua saiz purata nanozarah ZnO, NiO dan SnO2 telah ditambah masing-masing dengan komposisi x=0.02, 0.01 dan 0.01 % berat. Pita disediakan dengan kaedah serbuk dalam tiub (PIT) dan disinter pada suhu 845 °C selama 50 jam. Keputusan XRD menunjukkan bahawa semua sampel mempamerkan fasa dominan Bi2223 dengan fasa sampingan Bi2212. Mikrograf SEM menunjukkan pengecilan saiz butiran bagi semua sampel berbanding dengan sampel tulen yang menunjukkan butiran besar berbentuk plat. Ketumpatan arus genting bagi pita dengan penambahan nano zarah ZnO, NiO dan SnO2 adalah lebih tinggi daripada pita sampel tulen dalam medan magnet sifar. Keputusan ini menunjukkah bahawa zarah ZnO, NiO dan SnO2 bersaiz nanometer telah memperbaiki sifat angkutan arus pita Bi-2223 dan bertindak sebagai pusat pengepin fluks yang berkesan. Sampel dengan penambahan zarah bersaiz nanometer yang mendekati panjang koheren, ξ menunjukkan Jc yang paling tinggi. Jc tertinggi telah diperoleh dalam pita dengan ZnO (6 nm) dengan Jc=16200 A/cm2, NiO (8 nm) dengan Jc=15500 Am/cm2 dan SnO2 (8 nm) dengan Jc=10600 Am/cm2 pada 30 K. Kajian ini menunjukkan selain daripada tenaga terkondensasi daripada teras vorteks, tenaga magnet penuh vorteks melalui penambahan nanozarah boleh meningkatkan Jc.,The Transport critical current density of high-Tc superconductor decreases fast with increasing applied magnetic field due to the intergrain weak links and weak flux pinning capability. Additions of different nano-sized of ZnO, NiO and SnO2 to enhance superconducting properties and flux pinning in Bi1.6Pb0.4Sr2Ca2Cu3O10 superconductor in bulk and tape form have been investigated by X-ray diffraction technique (XRD), electrical resistance measurement and scanning electron microscopy (SEM). The coprecipitaion technique was used in the preparation of Bi1.6Pb0.4Sr2Ca2Cu3O10 (Bi-2223) superconductor powder. Two average sizes of NiO (8 and 16 nm), ZnO (6 and 30 nm) and SnO2 (8 and 48 nm) with nominal composition ranging from 0.00 to 0.05 wt. % were added separately into Bi1.6Pb0.4Sr2Ca2Cu3O10- (MO)x (M= Ni, Zn, Sn) before the final sintering process in air for 48 h at 850 °C. The critical temperature (Tc(R=0)) which is around 101 K for non-added sample decrease with NiO and SnO2 addition due to the decrease in the Bi2223 phase volume fraction. For samples with ZnO addition Tc(R=0) increased with 0.02 wt. % and decreased with further additions. All NiO and ZnO added samples showed onset transition temperature (Tc-onset) close to 112 K and 106-110 K for SnO2 added samples. The xray diffraction analyses indicated that majority of the diffraction peaks belonged to the Bi2223 phase with the low intensity peaks belonging to the Bi2212 phase. The critical current density (Jc) of the non-added sample was 21 mA/cm2 at 77 K. Jc for all added samples was higher than Jc of the non-added sample. All added samples showed smaller grains compared with the non-added sample. The Ag-sheathed Bi1.6Pb0.4Sr2Ca2Cu3O10 tapes were prepared based on the results of the highest Jc in the bulk samples. Two average sizes of ZnO, NiO and SnO2 nanoparticles were added separately with nominal compositions x=0.02, 0.01 and 0.01 wt. %, respectively. All tapes were prepared via powder-in-tube technique (PIT) and sintered at 845 °C for 50 h. The x-ray diffraction patterns indicated that Bi2223 phase was dominant with some peaks belonging to Bi2212 phase. SEM micrographs of all added tapes surface showed a decrease in the grain size compared to the non-added tape. The Jc in zero magnetic fields of tapes added with ZnO, NiO and SnO2 were higher compared with the non-added tape. The results indicated that ZnO, NiO and SnO2 nanoparticles enhanced the transport properties of Bi-2223 tapes and may act as effective flux pinning centres. Samples with nanoparticles having size closer to the coherence length, ξ showed a higher Jc. The highest Jc ware observed in 6 nm ZnO added tape (16200 A/cm2), 8 nm NiO added tape (15500 Am/cm2) and 8 nm SnO2 added tape (10600 Am/cm2) at 30 K. This work showed that apart from the condensation energy associated with their core, the full vortex magnetic energy by addition of nano-sized has the ability to enhance Jc.,PhD | - |
| dc.language.iso | eng | - |
| dc.publisher | UKM, Bangi | - |
| dc.relation | Faculty of Science and Technology / Fakulti Sains dan Teknologi | - |
| dc.rights | UKM | - |
| dc.subject | Superconductor | - |
| dc.subject | Superconductors | - |
| dc.title | Transport critical current density and flux pinning in Bi1.6Pb0.4Sr2Ca2Cu3O10 superconductor in bulk and tape form with different nano-sized NiO, ZnO and SnO2 additions | - |
| dc.type | Theses | - |
| dc.format.pages | 163 | - |
| dc.identifier.callno | TK454.4.S93A235 2014 tesis | - |
| dc.identifier.barcode | 001111 | - |
| Appears in Collections: | Faculty of Science and Technology / Fakulti Sains dan Teknologi | |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_80170+SOURCE1+SOURCE1.0.PDF Restricted Access | 37.6 MB | Adobe PDF |  View/Open |
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