Comparative study of the pressure effect on critical parameters of GdBa2Cu4O8 and YBa2Cu4O8

The effect of isotropic pressures P up to 5 kbar on the superconducting transition temperature Tc of the FeSe1−xTex system (x = 0, 0.85, 0.88, 0.90) is studied. For the first time, a change in the sign of the effect of pressure on Tc on going from FeSe to the tellurium-rich alloys is observed. This makes it possible to specify more precisely the form of the dependence of the pressure derivative dTc/dP on composition in this system. This dependence is compared with first principles calculations of the electron structure and magnetism of FeSe, FeTe, and FeSe0.5Te0.5 as functions of pressure, as well as with our earlier experimental data on the effect of pressure on the magnetic susceptibility of the normal state in FeSe and FeTe. This comparison is indicative of a competitive interrelationship between superconductivity and magnetism in tellurium rich FeSe1−xTex compounds.

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“…[28]). The cell was made of non-magnetic CuBe alloy with the inside and outside diameters of 1.6 mm and 5 mm, respectively.…”

Section: Experimental Details and Resultsmentioning

confidence: 99%

Interrelation of superconductivity and magnetism in FeSe1−xTex compounds. Pressure effects

Панфилов¹,

Pashchenko²,

Grechnev³

et al. 2014

Low Temperature Physics

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“…The pressure was measured by using the pressure dependence of the superconducting transition temperature of the built-in pressure sensor made from high purity tin. [31] Cooling and warming curves of the magnetisation were measured at each pressure at a rate of 1 K min À1 . Experimental data were corrected for diamagnetism by using Pascals constants.…”

Section: Methodsmentioning

confidence: 99%

Photomagnetism of a Series of Dinuclear Iron(II) Complexes

Létard¹,

Carbonera²,

Real³

et al. 2009

Chemistry A European J

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Spin crossover: The photomagnetic properties of a series of [{Fe(NCS)(py-X)}(2)(bpypz)(2)] (NCS=thiocyanate, py=pyridine, X=4-Mepy, py, 3-Mepy, 3-Clpy and 3-Brpy, and bpypz=3,5-bis(pyridine-2-yl)pyazolate) binuclear complexes are close to the antiferromagnetic response of [{Fe(NCS)(3,5-dmpy)}(3)(bpypz)(2)] (3,5-dmpy=3,5-dimethylpyrazine), which is characterised by two iron(II) metal ions in a high-spin (HS) electronic configuration (see figure).This paper describes the photomagnetic properties of a series of binuclear iron(II) complexes belonging to the [{Fe(NCS)(py-X)}(2)(bpypz)(2)] family (NCS=thiocyanate; py=pyridine; bpypz=3,5-bis(pyridine-2-yl)pyrazolate; and py-X=4-Mepy (1), py (3), 3-Mepy (4), 3-Clpy (5), and 3-Brpy (6)). All of these complexes display a complete thermal spin transition centred between 100 and 150 K, and undergo the light-induced excited-spin-state trapping (LIESST) effect at low temperatures. The T(LIESST) relaxation temperature of the photoinduced high-spin state for each compound has been determined. For all of the complexes, it has been found that the T(LIESST) curves at low temperature are close to the antiferromagnetic response of the [{Fe(NCS)(3,5-dmpy)}(2)(bpypz)(2)] (3,5-dmpy=3,5-dimethylpyridine) (7) complex that is characterised by two iron(II) metal ions in a HS electronic configuration, giving some evidence of a quantitative low spin-low spin-->high spin-high spin (LS-LS-->HS-HS) photoconversion process. Depending on the nature of the cooperativity, the kinetics have been treated with stretched exponential, simply exponential, or sigmoidal models. Interestingly, this series of dinuclear complexes follows a previously proposed linear relationship between the T(LIESST) and their thermal spin transition temperatures T(1/2): T(LIESST)=T(0)-0.3T(1/2). T(0) for these compounds is equal to 100 K. Based on this, and by using the empirical linear relationship found between the thermal spin transition and the Hammett constant, the HS-HS properties of complex 7 have been understood as a reflection of the physical impossibility that the T(LIESST) was higher than T(1/2). The close vicinity of the thermal spin-crossover phenomenon of 7 has been successfully checked by applying hydrostatic pressure.

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“…The pressure was measured using the pressure dependence of the superconducting transition temperature of a built-in pressure sensor made of high-purity tin [23]. Experimental data were corrected for diamagnetism using Pascal's constants.…”

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confidence: 99%

Particle‐Size Control and Patterning of a Charge‐Transfer Complex for Nanoelectronics

Tang

et al. 2005

Advanced Materials

100

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5-7 mm in length were used. The pressure was measured using the pressure dependence of the superconducting transition temperature of a built-in pressure sensor made of high-purity tin [23]. Experimental data were corrected for diamagnetism using Pascal's constants.Visible Absorption Spectroscopy under Hydrostatic Pressure: Full absorption spectra were recorded between 450 and 750 nm by using a Carl Zeiss PGS-2 spectrometer. The hydrostatic-pressure cell made of hardened beryllium bronze with NaCl as the pressure-transmitting medium operated in the pressure range 10 5 Pa < P < 3 GPa (accuracy ≈ ± 0.1 GPa). The pressure was measured using the pressure dependence of ruby [24].

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Comparative study of the pressure effect on critical parameters of GdBa2Cu4O8 and YBa2Cu4O8

Cited by 81 publications

References 18 publications

Interrelation of superconductivity and magnetism in FeSe1−xTex compounds. Pressure effects

Interrelation of superconductivity and magnetism in FeSe1−xTex compounds. Pressure effects

Photomagnetism of a Series of Dinuclear Iron(II) Complexes

Particle‐Size Control and Patterning of a Charge‐Transfer Complex for Nanoelectronics

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