ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
YBCO bulks with submicron Y2BaCuO5 particles have been prepared under oxygen partialpressures of 0.21atm and 1atm, respectively, by the powder melting process (PMP). Themicrostructures, oxygen contents and critical current densities of the samples have been investigated.The results showed that the sample grown under P(O2) = 1 atm contained Y2BaCuO5 particles with alittle bigger average size and had a slightly higher density of stacking faults than the one preparedunder P(O2) = 0.21 atm. Oxygen content measurements indicated that the as-grown sample underP(O2) = 1 atm had a higher oxygen content. After post-annealing in flowing oxygen, the oxygencontent of the P(O2) = 1 atm sample was still higher than that of the P(O2) = 0.21 atm sample. Theywere examined to be 6.94 and 6.88 with X-ray diffraction for the two oxygenated samples,respectively. Magnetization measurements have been performed on the two types of oxygenatedsamples and critical current densities (Jc) have been calculated based on the extended Bean criticalstate model. The P(O2) = 0.21 atm sample exhibits Jc values of 5.47×105 A/cm2 and 2.22×104 A/cm2in 1 T magnetic field at 20K and 77K, respectively. The P(O2) = 1 atm sample, meanwhile, has Jcvalues of 9.46×105 A/cm2 and 1.47×104 A/cm2 in 1 T magnetic field at 20K and 77K, respectively.Moreover, at 20K, the Jc of the P(O2) = 1 atm sample is higher than that of the P(O2) = 0.21 atmsample in an applied magnetic field up to 5 T. At 77K, however, the Jc of the P(O2) = 1 atm sampledrops more quickly than that of the P(O2) = 0.21 atm sample. The mechanisms of the differentmicrostructures, oxygen contents and magnetic field dependence behaviors of Jc for the two kinds ofsamples have been discussed
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/16/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.546-549.1887.pdf
