ISSN:
1662-0356
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Natural Sciences in General
,
Technology
Notes:
In order to grown epitaxial magnesium diboride MgB2 films, fibers and heterostructures,an hybrid physical-chemical vapour deposition (HPCVD) technique was developed, whichcombines physical vapour deposition (PVD) with chemical vapour deposition (CVD).The superconducting and normal-state properties of the MgB2 films are determined by the filmthickness. Above 3000Å, a Tc of 41.8 K, a ρ0 of 0.28 μΩ·cm, and a residual resistance ratio RRR ofover 30 were obtained. A carbon-containing metal-organic precursor was added to the carrier gas toachieve carbon doping. As the amount of carbon in the film increases, the resistivity increases, Tcdecreases, and the upper critical field increases dramatically as compared to clean films. The selffieldJc in the carbon doped film is lower than that in the clean film, but Jc remains relatively high tomuch higher magnetic fields, indicating stronger pinning. The carbon doping approach can be usedto produce MgB2 materials for high magnetic-field applications. We report on structural andsuperconducting properties of round MgB2 coated-conductor fibers on SiC fibers. The coating ispolycrystalline and composed of elongated crystallites. The pure MgB2 fiber shows a zeroresistance Tc of 39.3K. The carbon-alloyed fibers show a high upper critical field of 55T at 1.5Kand a high irreversibility field of 40T at 1.5 K. The result demonstrates great potential of MgB2coated conductors for superconducting magnets. We also report structural and transport proprietiesof MgB2/MgO and MgB2/AlN multilayers. The epitaxial MgB2/MgO/MgB2 trilayers were grownin-situ in the HPCVD system, while MgB2/AlN/MgB2 trilayers were deposited using an ex-situprocess. The results are promising for all-MgB2 planar Josephson junctions
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/42/transtech_doi~10.4028%252Fwww.scientific.net%252FAST.47.55.pdf
Permalink