Stabilization of High-Tc Phase of BiS2-Based Superconductor LaO0.5F0.5BiS2 Using High-Pressure Synthesis

Mizuguchi, Yoshikazu; Hiroi, Takafumi; Kajitani, Joe; Takatsu, Hiroshi; Kadowaki, Hiroko; Miura, Osuke

doi:10.7566/jpsj.83.053704

Cited by 63 publications

(62 citation statements)

References 19 publications

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“…The partial substitution of O by F is useful for this carrier doping. Although, optimal fluorine concentration is estimated to be around x = 0.5, the obtained superconducting transition temperature (T c ) is completely different between conventional solid state reactions and high pressure synthesis [2,[13][14][15]. In the case of the conventional solid state reaction, the T c of LaO 0.5 F 0.5 BiS 2 is obtained at only 3 K. On the other hand, the T c largely increases above 10 K by using high pressure synthesis.…”

Section: Introductionmentioning

confidence: 95%

High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure

Fujioka

Nagao

Denholme

et al. 2014

Applied Physics Letters

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We demonstrated a pressure-induced phase transition from a low-T c phase (3.5 K) to a high-T c phase (8.7 K) in single crystalline PrO 0.5 F 0.5 BiS 2 . The high-T c phase is easily observed even at 0.7 GPa by uniaxial pressure obtained from a geometric effect of a single crystal with an extremely-thin thickness. For this phase transition, superconducting anisotropy and the coherence length along the c axis change from γ = 20 to 9.3 and from ξ c = 0.56 to 0.71 nm respectively. It is suggested that a shrinkage in the c lattice constant by applied uniaxial pressure enhances the three dimensionality in the superconducting state.

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Section: Introductionmentioning

confidence: 95%

High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure

Fujioka

Nagao

Denholme

et al. 2014

Applied Physics Letters

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“…One-step high-pressure synthesis can also provide a higher-T c phase of LaO 0.5 F 0.5 BiS 2 under the optimal synthesis condition of 2 GPa and 700 ºC [24]. Crystal structure analysis revealed that the higher-T c phase of LaO 0.5 F 0.5 BiS 2 can be induced by uniaxial lattice contraction along the c axis [25]. Furthermore, Tomita et al reported that the lattice contraction under high pressure could be explained by a structural transition from tetragonal to monoclinic on the basis of analysis of the x-ray diffraction patterns under high pressure and optimization of the atomic positions by using density functional theory calculations [23].…”

Section: Introductionmentioning

confidence: 99%

Anisotropic upper critical field of theBiS2-based superconductorLaO0.5F0.5
Mizuguchi
¹
,
Miyake
²
,
Akiba
³

et al. 2014
Phys. Rev. B
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Superconducting properties under high magnetic fields for the novel BiS 2 -based layered superconductor LaO 0.5 F 0.5 BiS 2 (polycrystalline sample prepared using the high-pressure synthesis method) have been investigated. The anisotropy of the upper critical field was discussed by analyzing the temperature dependence of the temperature derivative of resistivity. under ambient pressure, we concluded that a larger anisotropy of superconductivity was not essential for the enhancement of T c , and lower anisotropy might be important for a higher T c in

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“…Tc of ~10 K [2,[16][17][18]. The emergence of bulk superconductivity and increase of Tc in the highpressure phase can be attributed to the structural phase transition from the tetragonal low-Tc phase to the monoclinic high-Tc phase [13].…”

mentioning

confidence: 99%

Evolution of Anisotropic Displacement Parameters and Superconductivity with Chemical Pressure in BiS₂-Based REO_0.5F_0.5BiS₂ (RE = La, Ce, Pr, and Nd)

et al. 2018

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In order to understand the mechanisms behind the emergence of superconductivity by the chemical pressure effect in REO0.5F0.5BiS2 (RE = La, Ce, Pr, and Nd), where bulk superconductivity is induced by the substitutions with a smaller-radius RE, we performed synchrotron powder X-ray diffraction, and analyzed the crystal structure and anisotropic displacement parameters. With the decrease of the RE 3+ ionic radius, the in-plane disorder of the S1 sites significantly decreased, very similar to the trend observed in the Se-substituted systems: LaO0.5F0.5BiS2-xSex and Eu0.5La0.5FBiS2-xSex. Therefore, the emergence of bulk superconductivity upon the suppression of the in-plane disorder at the chalcogen sites is a universal scenario for the BiCh2-based superconductors. In addition, we indicated that the amplitude of vibration along the c-axis of the in-plane chalcogen sites may be related to the Tc in the BiCh2-based superconductors. . In addition, the observed temperature dependence of the electrical resistivity was not metallic-like; it showed a weakly localized behavior in LaO1-xFxBiS2, although band calculations suggested that the electron-doped LaO1-xFxBiS2 should be metal [4,5,12]. These results suggested that the doped electrons were localized by the effect of structural disorder.In order to induce bulk superconductivity in LaO1-xFxBiS2, high pressure effects can be employed.The application of an external pressure induces bulk superconductivity with a Tc of ~10 K [13][14][15]. In addition, samples annealed under a high pressure (~2 GPa) also exhibit bulk superconductivity with aTc of ~10 K [2,[16][17][18]. The emergence of bulk superconductivity and increase of Tc in the highpressure phase can be attributed to the structural phase transition from the tetragonal low-Tc phase to the monoclinic high-Tc phase [13].Another approach to induce bulk superconductivity in the LaO1-xFxBiS2 system is to introduce a chemical pressure by an isovalent substitution, such as Ch (Ch: S, Se) and/or RE site substitutions. In LaO0.5F0.5BiS2-xSex, the substitutions of Se for the S sites induces bulk superconductivity with a Tc of ~3.8 K [19,20]. Another isovalent substitution is the RE site substitution. With the decrease of the RE 3+ (mean) ionic radius in REO0.5F0.5BiS2, the BiS2 layer becomes compressed, in particular along the ab-plane direction, and bulk superconductivity is induced [21]. As the isovalent substitution does not significantly affect the carrier concentration, the structural optimization induces superconductivity in the Ch-and RE-substituted systems. In order to analyze the essential factor for the emergence of the superconductivity, we considered the commonality of the chemical pressure effects between the Ch-and RE substitutions, by introducing the concept of an in-plane chemical pressure [22].The emergence of the bulk superconductivity in the LaO0.5F0.5BiS2-xSex system was explained by the decrease in the in-plane disorder of the chalcogen sites with the increase of the Se content, which was detected thro...

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Stabilization of High-T_c Phase of BiS₂-Based Superconductor LaO_0.5F_0.5BiS₂ Using High-Pressure Synthesis

Cited by 63 publications

References 19 publications

High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure

High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure

Anisotropic upper critical field of theBiS2-based superconductorLaO0.5F0.5
Mizuguchi
¹
,
Miyake
²
,
Akiba
³

et al. 2014
Phys. Rev. B
Self Cite
20
2
24
0
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Evolution of Anisotropic Displacement Parameters and Superconductivity with Chemical Pressure in BiS₂-Based REO_0.5F_0.5BiS₂ (RE = La, Ce, Pr, and Nd)

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Stabilization of High-Tc Phase of BiS2-Based Superconductor LaO0.5F0.5BiS2 Using High-Pressure Synthesis

Cited by 63 publications

References 19 publications

High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure

High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial pressure

Anisotropic upper critical field of theBiS2-based superconductorLaO0.5F0.5Mizuguchi1, Miyake2, Akiba3 et al. 2014Phys. Rev. BSelf Cite202240View full textAdd to dashboardCite

Evolution of Anisotropic Displacement Parameters and Superconductivity with Chemical Pressure in BiS2-Based REO0.5F0.5BiS2 (RE = La, Ce, Pr, and Nd)

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Stabilization of High-T_c Phase of BiS₂-Based Superconductor LaO_0.5F_0.5BiS₂ Using High-Pressure Synthesis

Anisotropic upper critical field of theBiS2-based superconductorLaO0.5F0.5
Mizuguchi
¹
,
Miyake
²
,
Akiba
³

et al. 2014
Phys. Rev. B
Self Cite
20
2
24
0
View full text Add to dashboard Cite

Evolution of Anisotropic Displacement Parameters and Superconductivity with Chemical Pressure in BiS₂-Based REO_0.5F_0.5BiS₂ (RE = La, Ce, Pr, and Nd)