TY - JOUR
T1 - Annealing study on (Hg,Tl) 2Ba2Can-1CunOy (n = 1-5) superconductors
AU - Tatsuki, T.
AU - Tokiwa-Yamamoto, A.
AU - Tamura, T.
AU - Adachi, S.
AU - Tanabe, K.
N1 - Funding Information:
This work was supported by NEDO for the R & D of Industrial Science and Technology Frontier Program.
PY - 1997/5/1
Y1 - 1997/5/1
N2 - We have investigated the effects of post-annealing on the Tc of (Hg,Tl)-22(n - 1)n (n =1-5) superconductors synthesized under high pressure. Reducing treatments in Ar, 3% H2/Ar or 5% H2/N2 were found to be effective in increasing the Tc of the n = 2-5 compounds, in particular for the (Hg,Tl)-2212 and (Hg,Tl)-2223 phases. Such enhancement in Tc is considered to be caused by the optimization of the hole concentrations in these compounds. The highest Tc of 120 K in this series was recorded for the n = 3 phase after post-annealing in 5% H2/N2. Though the 2201 sample did not show superconductivity even after the reducing treatments, superconductivity below 36 K was observed by substituting 40 % Nd for Ba. It is considered that our as-synthesized samples with n = 1-3 and n = 4, 5 are highly overdoped and slightly overdoped, respectively.
AB - We have investigated the effects of post-annealing on the Tc of (Hg,Tl)-22(n - 1)n (n =1-5) superconductors synthesized under high pressure. Reducing treatments in Ar, 3% H2/Ar or 5% H2/N2 were found to be effective in increasing the Tc of the n = 2-5 compounds, in particular for the (Hg,Tl)-2212 and (Hg,Tl)-2223 phases. Such enhancement in Tc is considered to be caused by the optimization of the hole concentrations in these compounds. The highest Tc of 120 K in this series was recorded for the n = 3 phase after post-annealing in 5% H2/N2. Though the 2201 sample did not show superconductivity even after the reducing treatments, superconductivity below 36 K was observed by substituting 40 % Nd for Ba. It is considered that our as-synthesized samples with n = 1-3 and n = 4, 5 are highly overdoped and slightly overdoped, respectively.
KW - Hg-Tl-Ba-Ca-Cu-O
KW - High pressure synthesis
KW - Homologous series
KW - Post annealing
KW - Superconductivity
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U2 - 10.1016/S0921-4534(97)00117-2
DO - 10.1016/S0921-4534(97)00117-2
M3 - Article
AN - SCOPUS:0031145315
SN - 0921-4534
VL - 278
SP - 160
EP - 168
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
IS - 3-4
ER -