Annealing study on (Hg,Tl) 2Ba2Can-1CunOy (n = 1-5) superconductors

T. Tatsuki; A. Tokiwa-Yamamoto; T. Tamura; S. Adachi; K. Tanabe

doi:10.1016/S0921-4534(97)00117-2

Annealing study on (Hg,Tl) ₂Ba₂Ca_n-1Cu_nO_y (n = 1-5) superconductors

T. Tatsuki, A. Tokiwa-Yamamoto, T. Tamura, S. Adachi, K. Tanabe

Research output: Contribution to journal › Article › peer-review

11 Citations (Scopus)

Abstract

We have investigated the effects of post-annealing on the T_c 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 T_c of the n = 2-5 compounds, in particular for the (Hg,Tl)-2212 and (Hg,Tl)-2223 phases. Such enhancement in T_c is considered to be caused by the optimization of the hole concentrations in these compounds. The highest T_c 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.

Original language	English
Pages (from-to)	160-168
Number of pages	9
Journal	Physica C: Superconductivity and its applications
Volume	278
Issue number	3-4
DOIs	https://doi.org/10.1016/S0921-4534(97)00117-2
Publication status	Published - 1997 May 1
Externally published	Yes

Keywords

Hg-Tl-Ba-Ca-Cu-O
High pressure synthesis
Homologous series
Post annealing
Superconductivity

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Energy Engineering and Power Technology
Electrical and Electronic Engineering

Access to Document

10.1016/S0921-4534(97)00117-2

Cite this

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title = "Annealing study on (Hg,Tl) 2Ba2Can-1CunOy (n = 1-5) superconductors",

abstract = "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.",

keywords = "Hg-Tl-Ba-Ca-Cu-O, High pressure synthesis, Homologous series, Post annealing, Superconductivity",

author = "T. Tatsuki and A. Tokiwa-Yamamoto and T. Tamura and S. Adachi and K. Tanabe",

note = "Funding Information: This work was supported by NEDO for the R & D of Industrial Science and Technology Frontier Program.",

year = "1997",

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doi = "10.1016/S0921-4534(97)00117-2",

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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.

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KW - Homologous series

KW - Post annealing

KW - Superconductivity

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