Diamagnetism and Cooper pairing above Tc in cuprates

Lu Li; Yayu Wang; Seiki Komiya; Shimpei Ono; Yoichi Ando; G. D. Gu; N. P. Ong

doi:10.1103/PhysRevB.81.054510

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Diamagnetism and Cooper pairing above Tc in cuprates

Lu Li, Yayu Wang, Seiki Komiya, Shimpei Ono, Yoichi Ando, G. D. Gu, N. P. Ong

DOI 10.1103/PhysRevB.81.054510 · Physical Review B

T1

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Abstract

In the cuprate superconductors, Nernst and torque magnetization experiments have provided evidence that the disappearance of the Meissner effect at Tc is caused by the loss of long-range phase coherence, rather than the vanishing of the pair condensate. Here we report a series of torque magnetization measurements on single crystals of La2−xSrxCuO4 (LSCO), Bi2Sr2−yLayCuO6 (Bi 2201), Bi2Sr2CaCu2O8+δ, and optimal YBa2Cu3O7. Some of the measurements were taken to fields as high as 45 T. Focusing on the magnetization above Tc, we show that the diamagnetic term Md appears at an onset temperature TonsetM high above Tc. We construct the phase diagram of both LSCO and Bi 2201 and show that TonsetM agrees with the onset temperature of the vortex Nernst signal Tonsetν. Our results provide thermodynamic evidence against a recent proposal that the high-temperature Nernst signal in LSCO arises from a quasiparticle contribution in a charge-ordered state.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	24	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	27	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38	Pressure not reported	unknown
Bi2Sr2-yLayCuO6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	12	Pressure not reported	unknown
Bi2Sr2-yLayCuO6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	18	Pressure not reported	unknown
Bi2Sr2-yLayCuO6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	30	Pressure not reported	unknown
Bi2Sr2-yLayCuO6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	88	Pressure not reported	unknown
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	50	Pressure not reported	unknown