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D. E. Farrell - One of the best experts on this subject based on the ideXlab platform.
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Superconducting magnetization above the Irreversibility Line in Tl2Ba2CuO6+δ
Physical Review B, 1998Co-Authors: C. Bergemann, A. Tyler, Andrew P. Mackenzie, J. R. Cooper, Stephen Julian, D. E. FarrellAbstract:Piezolever torque magnetometry has been used to measure the magnetization of superconducting ${\mathrm{Tl}}_{2}{\mathrm{Ba}}_{2}{\mathrm{CuO}}_{6+\mathrm{\ensuremath{\delta}}}.$ Three crystals with different levels of oxygen overdoping were investigated in magnetic fields up to 10 T. In all cases, the magnetization above the Irreversibility Line was found to depart from the behavior $M\ensuremath{\sim}\mathrm{ln}(\ensuremath{\eta}{H}_{c2}/H)$ of a simple London-like vortex liquid. In particular, for a strongly overdoped ${(T}_{c}=15\mathrm{K})$ crystal, the remnant superconducting order above the Irreversibility Line is characterized by a Linear diamagnetic response $(M\ensuremath{\sim}H)$ that persists well above ${T}_{c}$ and also up to the highest field employed.
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superconducting magnetization above the Irreversibility Line in tl2ba2cuo6 δ
Physical Review B, 1998Co-Authors: C. Bergemann, Andrew P. Mackenzie, J. R. Cooper, A W Tyler, S R Julian, D. E. FarrellAbstract:Piezolever torque magnetometry has been used to measure the magnetization of superconducting ${\mathrm{Tl}}_{2}{\mathrm{Ba}}_{2}{\mathrm{CuO}}_{6+\mathrm{\ensuremath{\delta}}}.$ Three crystals with different levels of oxygen overdoping were investigated in magnetic fields up to 10 T. In all cases, the magnetization above the Irreversibility Line was found to depart from the behavior $M\ensuremath{\sim}\mathrm{ln}(\ensuremath{\eta}{H}_{c2}/H)$ of a simple London-like vortex liquid. In particular, for a strongly overdoped ${(T}_{c}=15\mathrm{K})$ crystal, the remnant superconducting order above the Irreversibility Line is characterized by a Linear diamagnetic response $(M\ensuremath{\sim}H)$ that persists well above ${T}_{c}$ and also up to the highest field employed.
S. Tanaka - One of the best experts on this subject based on the ideXlab platform.
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Excitation field dependence, frequency dependence and anisotropy of the Irreversibility Line in MPMG YBa2Cu3O7 with Y2BaCuO5 inclusions
Superconductor Science and Technology, 1992Co-Authors: M. Slaski, L. T. Sagdahl, L.k. Heill, K. Fossheim, Masato Murakami, Hiroyuki Fujimoto, N. Koshizuka, S. TanakaAbstract:Most applications of superconducting materials require high critical current density. Melt-powder-melt-grown (MPMG) YBa2Cu3O7 with Y2BaCuO5 inclusions were found to have the highest critical current in bulk to date. The authors report a systematic study of the irreversible behaviour in the MPMG material. The Irreversibility Line was measured in external fields up to 8 T using an AC susceptibility technique. Large anisotropy of the Irreversibility Line for different orientations of the field was observed. The frequency dependence was found to be logarithmic in the range 10 to 105 Hz. In order to study the excitation field dependence in detail, they applied AC fields from 0.01 G up to 30 G.
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Anisotropy of the Irreversibility Line in MPMG YBa2Cu3O7-δ with Y2BaCuO5 inclusions
Physica C: Superconductivity, 1991Co-Authors: M. Slaski, L. T. Sagdahl, L.k. Heill, K. Fossheim, Masato Murakami, Hiroyuki Fujimoto, N. Koshizuka, S. TanakaAbstract:Abstract A systematic study of the magnetic Irreversibility behavior in the MPMG (melt-powder-melt-grown) material with Y 2 BaCuO 5 inclusions have been performed. The Irreversibility Line was measured in external fields up to 8 T using an ac susceptibility technique. Large anisotropy of the Irreversibility Line measured in fields parallel and perpendicular to the ab-plane was observed. The frequency dependence of the Irreversibility Line was found to be logarithmic. The excitation field dependence of the Irreversibility Line is also determined.
C. Bergemann - One of the best experts on this subject based on the ideXlab platform.
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Superconducting magnetization above the Irreversibility Line in Tl2Ba2CuO6+δ
Physical Review B, 1998Co-Authors: C. Bergemann, A. Tyler, Andrew P. Mackenzie, J. R. Cooper, Stephen Julian, D. E. FarrellAbstract:Piezolever torque magnetometry has been used to measure the magnetization of superconducting ${\mathrm{Tl}}_{2}{\mathrm{Ba}}_{2}{\mathrm{CuO}}_{6+\mathrm{\ensuremath{\delta}}}.$ Three crystals with different levels of oxygen overdoping were investigated in magnetic fields up to 10 T. In all cases, the magnetization above the Irreversibility Line was found to depart from the behavior $M\ensuremath{\sim}\mathrm{ln}(\ensuremath{\eta}{H}_{c2}/H)$ of a simple London-like vortex liquid. In particular, for a strongly overdoped ${(T}_{c}=15\mathrm{K})$ crystal, the remnant superconducting order above the Irreversibility Line is characterized by a Linear diamagnetic response $(M\ensuremath{\sim}H)$ that persists well above ${T}_{c}$ and also up to the highest field employed.
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superconducting magnetization above the Irreversibility Line in tl2ba2cuo6 δ
Physical Review B, 1998Co-Authors: C. Bergemann, Andrew P. Mackenzie, J. R. Cooper, A W Tyler, S R Julian, D. E. FarrellAbstract:Piezolever torque magnetometry has been used to measure the magnetization of superconducting ${\mathrm{Tl}}_{2}{\mathrm{Ba}}_{2}{\mathrm{CuO}}_{6+\mathrm{\ensuremath{\delta}}}.$ Three crystals with different levels of oxygen overdoping were investigated in magnetic fields up to 10 T. In all cases, the magnetization above the Irreversibility Line was found to depart from the behavior $M\ensuremath{\sim}\mathrm{ln}(\ensuremath{\eta}{H}_{c2}/H)$ of a simple London-like vortex liquid. In particular, for a strongly overdoped ${(T}_{c}=15\mathrm{K})$ crystal, the remnant superconducting order above the Irreversibility Line is characterized by a Linear diamagnetic response $(M\ensuremath{\sim}H)$ that persists well above ${T}_{c}$ and also up to the highest field employed.
L Schultz - One of the best experts on this subject based on the ideXlab platform.
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upper critical field and Irreversibility Line in superconducting mgb2
Solid State Communications, 2001Co-Authors: G. Fuchs, K. Nenkov, K H Muller, A Handstein, V N Narozhnyi, D Eckert, M Wolf, L SchultzAbstract:Abstract The upper critical field Hc2(T) of sintered pellets of the recently discovered MgB2 superconductor was investigated by transport, ac susceptibility and dc magnetization measurements in magnetic fields up to 16 T covering a temperature range between T c ∽39 K and T=3 K ∽0.1T c . The temperature dependence of the upper critical field, Hc2(T), shows a positive curvature near Tc similar to that found for the borocarbides YNi2B2C and LuNi2B2C indicating that MgB2 is in the clean limit. The Irreversibility Line was consistently determined from dc magnetization measurements and from the imaginary component of ac susceptibility. The Irreversibility field was found to increase up to 8.5 T at 10 K.
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upper critical field and Irreversibility Line in superconducting mgb_2
arXiv: Superconductivity, 2001Co-Authors: G. Fuchs, K. Nenkov, K H Muller, A Handstein, V N Narozhnyi, D Eckert, M Wolf, L SchultzAbstract:The upper critical field Hc2(T) of sintered pellets of the recently discovered MgB_2 superconductor was investigated by transport, ac susceptibility and dc magnetization measurements in magnetic fields up to 16 T covering a temperature range between Tc ~ 39 K and T = 3 K ~ 0.1Tc. The temperature dependence of the upper critical field, Hc2(T), shows a positive curvature near Tc similar to that found for the borocarbides YNi_2B_2C and LuNi_2B_2C indicating that MgB_2 is in the clean limit. The Irreversibility Line was consistently determined from dc magnetization measurements and from the imaginary component of ac susceptibility. The Irreversibility field was found to increase up to 8.5 T at 10 K.
Sergei Sergeenkov - One of the best experts on this subject based on the ideXlab platform.
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On field-induced Irreversibility Line crossover in deoxygenated weak-links-containing superconductors
Solid State Communications, 1991Co-Authors: Sergei SergeenkovAbstract:Abstract A possible explanation of the experimentally observed field-induced crossover of the Irreversibility Line Tc(H) in deoxygenated high-Tc superconductors is proposed via a new model of granular superconductor with dislocation-mediated grain boundary weak links. The model predicts magnetic field and oxygen deficiency dependence of the Irreversibility Line power exponent q(δ,H). It is shown that for an intermediate field region and small deficiency (δ∼0.01) the model leads to the transition from a de Almeida-Thouless-like Line (with q= 2 3 ) to a Gabay-Toulouse-like one (with q=2) with increasing the field, whereas for high enough deficiency (δ∼0.5) the system chooses another path in the H-T plane from H 2 3 to H 1 4 , practically within the same field interval.
