Resistive upper critical fields and irreversibility lines of optimally doped high-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>cuprates

Ando, Yoichi; Boebinger, G. S.; Passner, A.; Schneemeyer, Lynn; Kimura, T.; Okuya, M.; Watauchi, Satoshi; Shimoyama, Jun–ichi; Kishio, K.; Tamasaku, Kenji; Ichikawa, Noriya; Uchida, S.

doi:10.1103/physrevb.60.12475

Cited by 158 publications

(168 citation statements)

References 27 publications

(37 reference statements)

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“…The resistance decreases rapidly below the zero-field transition temperature T c (H=0T)=29K, and becomes zero below the irreversibility temperature T irr (H). The white circles locate T irr and show that it is a rapid function of applied field, so that even for fields much smaller than the upper critical field (H c2 (x=0.10)~45T [11]), perfect conductivity does not occur until the temperature is well below T c (H=0T).…”

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confidence: 99%

Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor

Lake

Rønnow

Christensen

et al. 2002

Nature

538

508

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One view of the cuprate high-transition temperature (high-T c ) superconductors is that they are conventional superconductors where the pairing occurs between weakly interacting quasiparticles, which stand in one-to-one correspondence with the electrons in ordinary metals -although the theory has to be pushed to its limit [1]. An alternative view is that the electrons organize into collective textures (e.g. charge and spin stripes) which cannot be mapped onto the electrons in ordinary metals. The phase diagram, a complex function of various parameters (temperature, doping and magnetic field), should then be approached using quantum field theories of objects such as textures and strings, rather than point-like electrons [2,3,4,5,6]. In an external magnetic field, magnetic flux penetrates type-II superconductors via vortices, each carrying one flux quantum [7]. The vortices form lattices of resistive material embedded in the non-resistive superconductor and can reveal the nature of the ground state -e.g. a conventional metal or an ordered, striped phase -which would have appeared had superconductivity not intervened. Knowledge of this ground state clearly provides the most appropriate starting point for a pairing theory. Here we report that for one high-T c superconductor, the applied field which imposes the vortex lattice, also induces antiferromagnetic order. Ordinary quasiparticle pictures cannot account for the nearly fieldindependent antiferromagnetic transition temperature revealed by our measurements.La 2-x Sr x CuO 4 , is the simplest high-T c superconductor. The undoped compound is an insulating antiferromagnet, where the spin moments on adjacent Cu 2+ ions are antiparallel [8]. Introduction of charge carriers via Sr doping reduces the ordered moment until it vanishes at x<0.13. In addition, for x>0.05 the commensurate antiferromagnetism is replaced by incommensurate order [2,3,9,10], where the repeat distance for the pattern of ordered moments is substantially larger than the spacing between neighbouring copper ions. La 2-x Sr x CuO 4 becomes a 2 superconductor for Sr dopings of 0.06

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mentioning

confidence: 99%

Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor

Lake

Rønnow

Christensen

et al. 2002

Nature

538

508

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“…the in-plane resistivity ρ ab (T ,H ) in pulsed and d.c. magnetic fields. Previous transport studies in cuprates identified H c2 (T ) with the 'knee' at or near the top of the ρ ab (T ) curve or the temperature at which ρ ab (H ) attained a certain fraction of the normal-state value 15 . Either technique would lead to a H c2 (T ) line with a markedly different shape from that determined by the Nernst effect, for example.…”

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Phase-fluctuating superconductivity in overdoped La2−xSrxCuO4

Rourke

Mouzopoulou

et al. 2011

Nature Phys

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In underdoped cuprate superconductors, phase stiffness is low and long-range superconducting order is destroyed readily by thermally generated vortices (and anti-vortices), giving rise to a broad temperature regime above the zero-resistive state in which the superconducting phase is incoherent 1-4 . It has often been suggested that these vortex-like excitations are related to the normal-state pseudogap or some interaction between the pseudogap state and the superconducting state 5-10 . However, to elucidate the precise relationship between the pseudogap and superconductivity, it is important to establish whether this broad phase-fluctuation regime vanishes, along with the pseudogap 11 , in the slightly overdoped region of the phase diagram where the superfluid pair density and correlation energy are both maximal 12 . Here we show, by tracking the restoration of the normal-state magnetoresistance in overdoped La 2−x Sr x CuO 4 , that the phase-fluctuation regime remains broad across the entire superconducting composition range. The universal low phase stiffness is shown to be correlated with a low superfluid density 1 , a characteristic of both underdoped and overdoped cuprates 12-14 . The formation of the pseudogap, by inference, is therefore both independent of and distinct from superconductivity.In underdoped cuprates, an energy gap (pseudogap), of as yet unknown origin, appears in the electronic density of states well before superconductivity develops. The continuous evolution 6 of the pseudogap into the superconducting gap, combined with similarities in their gap magnitudes and symmetries 5 , has led to suggestions that the pseudogap is a precursor superconducting state 7-10 characterized by a broad temperature region over which the superconducting order parameter is finite but the phase fluctuates 3,4 . This picture of precursor pairing remains controversial however and is challenged by measurements indicating that the pseudogap itself closes at a critical doping concentration 11 , slightly beyond optimal doping, where superconductivity is most robust 12 . As it stands, there have been very few studies to date of the fluctuating superconductivity in overdoped, superconducting cuprates to establish the precise relationship between the pseudogap and phase fluctuation regimes.To address this, we focus here on the evolution of the upper critical field H c2 with temperature, as inferred by measurements of the in-plane resistivity ρ ab (T ,H ) in pulsed and d.c. magnetic fields. Previous transport studies in cuprates identified H c2 (T ) with the 'knee' at or near the top of the ρ ab (T ) curve or the temperature at which ρ ab (H ) attained a certain fraction of the normal-state value 15 . Either technique would lead to a H c2 (T ) line with a markedly different shape from that determined by the Nernst effect, for example. In this study, we adopt an alternative approach 16,17 , using the evolution of the transverse magnetoresistance ρ ab (H )(= ρ ab (H )− ρ ab (0) with H c) with temperature, field and doping, as ...

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“…Apart from the inter-planar correlations, it is important to establish whether it is the coupling of the field to the spins or to the motion of the electrons which is responsible for the field-induced order. Clarification would permit rigorous scrutiny of the idea that the vortices in the superconductors nucleate the field-induced order, a phenomenon rather different from the Zeemaninduced pair-breaking likely to be responsible for the high-field superconductorinsulator transition characteristic of the underdoped cuprates 17,18 .The standard technique for measurement of antiferromagnetic order is neutron diffraction, the magnetic analogue of structural x-ray diffraction. In all previous experiments to characterize the field-induced order in high-temperature superconductors, the field was vertical and approximately perpendicular to the CuO 2 planes.…”

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confidence: 99%

mentioning

confidence: 99%

Three-dimensionality of field-induced magnetism in a high-temperature superconductor

et al. 2005

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Many physical properties of high-temperature (high-T c ) superconductors are two-dimensional phenomena derived from their square planar CuO 2 building blocks. This is especially true of the magnetism from the copper ions. As mobile charge carriers enter the CuO 2 layers, the antiferromagnetism of the parent insulators, where each copper spin is antiparallel to its nearest neighbours 1 , evolves into a fluctuating state where the spins show tendencies towards magnetic order of a longer periodicity. For certain charge carrier densities, quantum fluctuations are sufficiently suppressed to yield static longperiod order 2,3,4,5,6 , and external magnetic fields also induce such order 7,8,9,10,11,12 . Here we show that in contrast to the chemically-controlled order in superconducting samples, the field-induced order in these same samples is actually three-dimensional, implying significant magnetic linkage between the CuO 2 planes. The results are important because they show that there are threedimensional magnetic couplings which survive into the superconducting state, and coexist with the crucial inter-layer couplings responsible for threedimensional superconductivity. Both types of coupling will straighten the vortex lines, implying that we have finally established a direct link between technical superconductivity, which requires zero electrical resistance in an applied magnetic field and depends on vortex dynamics, and the underlying antiferromagnetism of the cuprates.La 2 CuO 4 is the parent compound of the original high temperature superconductor La 2-x Ba x CuO 4 discovered by Bednorz and Muller 13 nearly two decades ago. Here we examine the related cuprate La 2-x Sr x CuO 4 (LSCO) with x=0.10 and a superconducting transition temperature of T c =29 K. Previous measurements indicate weak, long-period magnetic order derived from defects which differ from sample to sample, and stronger field-induced order with all of the hallmarks of an intrinsic effect 8 , including sample-independence and a sharp onset temperature indistinguishable from T c . While these measurements have stimulated theory 14,15,16 , they could only probe magnetism within the CuO 2 planes, and thus were insensitive to inter-planar interactions. The latter are ultimately responsible for technologically useful three-dimensional superconductivity and for key features of the competition between magnetism and superconductivity 16 . Apart from the inter-planar correlations, it is important to establish whether it is the coupling of the field to the spins or to the motion of the electrons which is responsible for the field-induced order. Clarification would permit rigorous scrutiny of the idea that the vortices in the superconductors nucleate the field-induced order, a phenomenon rather different from the Zeemaninduced pair-breaking likely to be responsible for the high-field superconductorinsulator transition characteristic of the underdoped cuprates 17,18 .The standard technique for measurement of antiferromagnetic order is neutron diffraction, the mag...

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Resistive upper critical fields and irreversibility lines of optimally doped high-Tccuprates

Cited by 158 publications

References 27 publications

Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor

Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor

Phase-fluctuating superconductivity in overdoped La2−xSrxCuO4

Three-dimensionality of field-induced magnetism in a high-temperature superconductor

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