THESIS
2019
77 pages, 19 unnumbered pages : illustrations ; 30 cm
Abstract
In this research, deposition of oxide based high temperature superconducting material,
namely Yttrium barium copper oxide (YBCO) into mesoporous structure is achieved by a
modified chemical vapor deposition (CVD) and with addition aid of ball-milling. Substrate
including mesoporous silica Santa Barbara Amorphous No. 15 (SBA-15) with pore diameter
of 8nm to 14 nm and Anodic alumina oxide (AAO) with pore diameter of 30 nm to 60nm are
used as template.
The main objective of this research is to produce an array of YBCO nanowires with diameter
smaller or similar to the value currently reported from journals. During the time of research,
the smallest diameter reported for YBCO is 38nm. YBCO powders are fabricated via hand
grinding and ball milling of precursors of Yttrium, Barium and...[
Read more ]
In this research, deposition of oxide based high temperature superconducting material,
namely Yttrium barium copper oxide (YBCO) into mesoporous structure is achieved by a
modified chemical vapor deposition (CVD) and with addition aid of ball-milling. Substrate
including mesoporous silica Santa Barbara Amorphous No. 15 (SBA-15) with pore diameter
of 8nm to 14 nm and Anodic alumina oxide (AAO) with pore diameter of 30 nm to 60nm are
used as template.
The main objective of this research is to produce an array of YBCO nanowires with diameter
smaller or similar to the value currently reported from journals. During the time of research,
the smallest diameter reported for YBCO is 38nm. YBCO powders are fabricated via hand
grinding and ball milling of precursors of Yttrium, Barium and Copper in the form of
Dipivaloymethane (DPM). The powders undergo CVD with the selected substrate, which
allow deposition inside the pore and formation of YBCO nanowires.
For SBA-15/YBCO, the mixture is directly characterized by TEM as the SBA-15 structure
can be see-through under TEM. For the AAO/YBCO, the template is cleanse with sodium
hydroxide (NaOH) to remove the AAO, in which bundles of YBCO nanowires are obtained
for TEM analysis. The template is characterized using BET, while product is characterized
using TEM, EDX and also XRD.
The SBA-15/YBCO combination is unable to produce any YBCO nanowires due to the small
pore size. For the AAO/YBCO mixture, YBCO nanowires with range of 35nm to 100nm are
produced abundantly with the use of AAO template with 35nm or 40nm. The
superconductivity of metal and oxide-based nanowires are expected to greatly enhance when
the product nanowires reach or lower than the coherence length. The coherence length of
YBCO is around 3~5 nm. Therefore, while thin YBCO nanowires are produced, their
physical and electrical properties are not expected to be differ from the bulk counterpart.
Post a Comment