TY - JOUR
T1 - Thermogravimetric study on HgBa2Can-1CunO2(n+1)+δ (n = 1, 2, 3) superconductors at various oxygen partial pressures
AU - Tokiwa-Yamamoto, Ayako
AU - Fukuoka, Atsushi
AU - Itoh, Makoto
AU - Adachi, Seiji
AU - Yamauchi, H.
AU - Tanabe, Keiichi
N1 - Funding Information:
The authorsw ouldlike to thankM . Karppineno f Tokyo Instituteo f Technologfyo r her usefuld iscus-sions. This work was supportedb y NEDO for the R&D of IndustriaSl ciencea ndT echnologFyr ontier Program.
PY - 1996/10/1
Y1 - 1996/10/1
N2 - The oxygen non-stoichiometry of HgBa2Can-1CunO2(n+1)+δ (Hg-12(n - 1)n, n = 1, 2, 3) superconductors was studied by thermogravimetric analysis (TGA) in a flowing gas atmosphere with various partial pressures of oxygen ranging from 10-5 to 10 atm. In 1 atm oxygen, irreversible reactions, probably corresponding to vaporization of Hg, were observed above about 420, 480 and 510°C for Hg-1201, 1212 and 1223 samples, respectively. Reversible reactions with oxygen absorption and desorption were confirmed below these temperatures. By controlling the oxygen partial pressure during the heating process up to 300°C and a subsequent cooling process, we obtained Hg-12(n - 1)n samples with various oxygen contents. The superconducting properties of these samples were also studied. It was found that the oxygen non-stoichiometry of Hg-12(n - 1)n superconductors is very sensitive to the oxidizing atmosphere when they are annealed, even below 300°C.
AB - The oxygen non-stoichiometry of HgBa2Can-1CunO2(n+1)+δ (Hg-12(n - 1)n, n = 1, 2, 3) superconductors was studied by thermogravimetric analysis (TGA) in a flowing gas atmosphere with various partial pressures of oxygen ranging from 10-5 to 10 atm. In 1 atm oxygen, irreversible reactions, probably corresponding to vaporization of Hg, were observed above about 420, 480 and 510°C for Hg-1201, 1212 and 1223 samples, respectively. Reversible reactions with oxygen absorption and desorption were confirmed below these temperatures. By controlling the oxygen partial pressure during the heating process up to 300°C and a subsequent cooling process, we obtained Hg-12(n - 1)n samples with various oxygen contents. The superconducting properties of these samples were also studied. It was found that the oxygen non-stoichiometry of Hg-12(n - 1)n superconductors is very sensitive to the oxidizing atmosphere when they are annealed, even below 300°C.
UR - http://www.scopus.com/inward/record.url?scp=0030261413&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030261413&partnerID=8YFLogxK
U2 - 10.1016/0921-4534(96)00470-4
DO - 10.1016/0921-4534(96)00470-4
M3 - Article
AN - SCOPUS:0030261413
SN - 0921-4534
VL - 269
SP - 354
EP - 360
JO - Physica C: Superconductivity and its applications
JF - Physica C: Superconductivity and its applications
IS - 3-4
ER -