Evolution of superconductivity in isovalent Te-substituted K xFe2-ySe2 crystals

Toshinori Ozaki; Hiroyuki Takeya; Keita Deguchi; Satoshi Demura; Hiroshi Hara; Tohru Watanabe; Saleem James Denholme; Hiroyuki Okazaki; Masaya Fujioka; Yoshiko Yokota; Takahide Yamaguchi; Yoshihiko Takano

doi:10.1088/0953-2048/26/5/055002

Evolution of superconductivity in isovalent Te-substituted K _xFe_2-ySe₂ crystals

Toshinori Ozaki, Hiroyuki Takeya, Keita Deguchi, Satoshi Demura, Hiroshi Hara, Tohru Watanabe, Saleem James Denholme, Hiroyuki Okazaki, Masaya Fujioka, Yoshiko Yokota, Takahide Yamaguchi, Yoshihiko Takano

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12 Citations (Scopus)

Abstract

We report the evolution of superconductivity and the phase diagram of the K_xFe_2-ySe_2-zTe_z (z = 0-0.6) crystals grown by a one-step synthesis. The one-step synthesis is much simpler than a conventional process to grow the K_xFe_2-ySe₂ system. No structural transition is observed in any crystals, while lattice parameters exhibit a systematic expansion with increasing Te content. The T _c exhibits a gradual decrease with increasing Te content from K at z = 0 to K at z = 0.5, followed by a sudden suppression of superconductivity at z = 0.6. Upon approaching a Te concentration of 0.6, the shielding volume fraction decreases and eventually drops to zero. Simultaneously, hump positions in the ρ-T curve shift to lower temperatures. These results suggest that isovalent substitution of Te for Se in K_xFe_2-ySe₂ crystals suppresses the superconductivity in this system.

Original language	English
Article number	055002
Journal	Superconductor Science and Technology
Volume	26
Issue number	5
DOIs	https://doi.org/10.1088/0953-2048/26/5/055002
Publication status	Published - May 2013
Externally published	Yes

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title = "Evolution of superconductivity in isovalent Te-substituted K xFe2-ySe2 crystals",

abstract = "We report the evolution of superconductivity and the phase diagram of the KxFe2-ySe2-zTez (z = 0-0.6) crystals grown by a one-step synthesis. The one-step synthesis is much simpler than a conventional process to grow the KxFe2-ySe2 system. No structural transition is observed in any crystals, while lattice parameters exhibit a systematic expansion with increasing Te content. The T c exhibits a gradual decrease with increasing Te content from K at z = 0 to K at z = 0.5, followed by a sudden suppression of superconductivity at z = 0.6. Upon approaching a Te concentration of 0.6, the shielding volume fraction decreases and eventually drops to zero. Simultaneously, hump positions in the ρ-T curve shift to lower temperatures. These results suggest that isovalent substitution of Te for Se in KxFe2-ySe2 crystals suppresses the superconductivity in this system.",

author = "Toshinori Ozaki and Hiroyuki Takeya and Keita Deguchi and Satoshi Demura and Hiroshi Hara and Tohru Watanabe and {James Denholme}, Saleem and Hiroyuki Okazaki and Masaya Fujioka and Yoshiko Yokota and Takahide Yamaguchi and Yoshihiko Takano",

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doi = "10.1088/0953-2048/26/5/055002",

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T1 - Evolution of superconductivity in isovalent Te-substituted K xFe2-ySe2 crystals

AU - Ozaki, Toshinori

AU - Takeya, Hiroyuki

AU - Deguchi, Keita

AU - Demura, Satoshi

AU - Hara, Hiroshi

AU - Watanabe, Tohru

AU - James Denholme, Saleem

AU - Okazaki, Hiroyuki

AU - Fujioka, Masaya

AU - Yokota, Yoshiko

AU - Yamaguchi, Takahide

AU - Takano, Yoshihiko

PY - 2013/5

Y1 - 2013/5

N2 - We report the evolution of superconductivity and the phase diagram of the KxFe2-ySe2-zTez (z = 0-0.6) crystals grown by a one-step synthesis. The one-step synthesis is much simpler than a conventional process to grow the KxFe2-ySe2 system. No structural transition is observed in any crystals, while lattice parameters exhibit a systematic expansion with increasing Te content. The T c exhibits a gradual decrease with increasing Te content from K at z = 0 to K at z = 0.5, followed by a sudden suppression of superconductivity at z = 0.6. Upon approaching a Te concentration of 0.6, the shielding volume fraction decreases and eventually drops to zero. Simultaneously, hump positions in the ρ-T curve shift to lower temperatures. These results suggest that isovalent substitution of Te for Se in KxFe2-ySe2 crystals suppresses the superconductivity in this system.

AB - We report the evolution of superconductivity and the phase diagram of the KxFe2-ySe2-zTez (z = 0-0.6) crystals grown by a one-step synthesis. The one-step synthesis is much simpler than a conventional process to grow the KxFe2-ySe2 system. No structural transition is observed in any crystals, while lattice parameters exhibit a systematic expansion with increasing Te content. The T c exhibits a gradual decrease with increasing Te content from K at z = 0 to K at z = 0.5, followed by a sudden suppression of superconductivity at z = 0.6. Upon approaching a Te concentration of 0.6, the shielding volume fraction decreases and eventually drops to zero. Simultaneously, hump positions in the ρ-T curve shift to lower temperatures. These results suggest that isovalent substitution of Te for Se in KxFe2-ySe2 crystals suppresses the superconductivity in this system.

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DO - 10.1088/0953-2048/26/5/055002

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SN - 0953-2048

VL - 26

JO - Superconductor Science and Technology

JF - Superconductor Science and Technology

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ER -

Evolution of superconductivity in isovalent Te-substituted K _xFe_2-ySe₂ crystals

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