Experimental techniques for pulsed magnetic fields

Herlach, F.; Agosta, C. C.; Bogaerts, Ria; Boon, Willy; Deckers, I.; Keyser, A. De; Harrison, N.; Lagutin, A. S.; Li, Liang; Trappeniers, Lieven; Vanacken, Johan; Bockstal, L. Van; Esch, A. Van

doi:10.1016/0921-4526(95)00463-7

Cited by 30 publications

(7 citation statements)

References 9 publications

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“…To minimize the effects of flux dissipation heating in pulsed magnetic fields, the sample is immersed in liquid 4 He throughout the experiment [66,67], and only the oscillations observed during the falling field are considered for detailed analysis. On taking such precautions, effective mass estimates are obtained that are comparable to those obtained in samples of the same oxygen concentration in static magnetic fields [12].…”

Section: Appendix a Experimental Detailsmentioning

confidence: 99%

Compensated electron and hole pockets in an underdoped high-Tcsuperconductor

et al. 2010

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We report quantum oscillations in the underdoped high-temperature superconductor YBa 2 Cu 3 O 6+x over a wide range in magnetic field 28Յ 0 H Յ 85 T corresponding to Ϸ12 oscillations, enabling the Fermi surface topology to be mapped to high resolution. As earlier reported by Sebastian et al. ͓Nature ͑London͒ 454, 200 ͑2008͔͒, we find a Fermi surface comprising multiple pockets, as revealed by the additional distinct quantum oscillation frequencies and harmonics reported in this work. We find the originally reported broad lowfrequency Fourier peak at Ϸ535 T to be clearly resolved into three separate peaks at Ϸ460, Ϸ532, and Ϸ602 T, in reasonable agreement with the reported frequencies of Audouard et al. ͓Phys. Rev. Lett. 103, 157003 ͑2009͔͒. However, our increased resolution and angle-resolved measurements identify these frequencies to originate from two similarly sized pockets with greatly contrasting degrees of interlayer corrugation. The spectrally dominant frequency originates from a pocket ͑denoted ␣͒ that is almost ideally two-dimensional in form ͑exhibiting negligible interlayer corrugation͒. In contrast, the newly resolved weaker adjacent spectral features originate from a deeply corrugated pocket ͑denoted ␥͒. On comparison with band structure, the d-wave symmetry of the interlayer dispersion locates the minimally corrugated ␣ pocket at the "nodal" point k nodal = ͑ / 2, / 2͒, and the significantly corrugated ␥ pocket at the "antinodal" point k antinodal = ͑ ,0͒ within the Brillouin zone. The differently corrugated pockets at different locations indicate creation by translational symmetry breaking-a spin-density wave has been suggested from the suppression of Zeeman splitting for the spectrally dominant pocket. In a broken-translational symmetry scenario, symmetry points to the nodal ͑␣͒ pocket corresponding to holes, with the weaker antinodal ͑␥͒ pocket corresponding to electrons-likely responsible for the negative Hall coefficient reported by LeBoeuf et al. ͓Nature ͑London͒ 450, 533 ͑2007͔͒. Given the similarity in ␣ and ␥ pocket volumes, their opposite carrier type and the previous report of a diverging effective mass in Sebastian et al. ͓Proc. Nat. Am. Soc. 107, 6175 ͑2010͔͒, we discuss the possibility of a secondary Fermi surface instability at low dopings of the excitonic insulator type, associated with the metal-insulator quantum critical point. Its potential involvement in the enhancement of superconducting transition temperatures is also discussed.

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Section: Appendix a Experimental Detailsmentioning

confidence: 99%

Compensated electron and hole pockets in an underdoped high-Tcsuperconductor

et al. 2010

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“…The magnetoresistivity measurements were performed in a temperature range between 1.5 K and 300 K in a cryostat equipped with a superconducting magnet coil generating fields up to 12 T and magnetization was measured in a SQUID magnetometer in fields up to 5 T. For magnetization studies at higher magnetic fields we employed the pulsed fields setup described in ref. [21], allowing to measure magnetization induced by field pulses up to 50 T on a timescale of 10 -20 ms. The detected signal is hereby the voltage induced in highly sensitive pick-up coils, being proportional to the time derivative of the magnetization ∂M/∂t, which is electronically integrated to M(B).…”

Section: Methodsmentioning

confidence: 99%

Influence of the cooperative Jahn-Teller effect on the transport and magnetic properties ofLa7/8Sr1/8<

et al. 2000

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The low-doped magnetic perovskite La 7/8 Sr 1/8 MnO 3 undergoes within the paramagneticsemiconducting phase a first-order structural transition due to antiferrodistorsive ordering of Jahn-Teller deformed MnO 6 octahedra. This allows to study not only the influence of the spin configuration on the magneto-transport properties (CMR effect) but also the role of orbital order and disorder. The orbital ordering transition (at 269 K in zero magnetic field) causes a doubling of the resistivity (regardless of the CMR effect in applied magnetic fields) and a drop of the paramagnetic susceptibility. The latter might be interpreted in terms of a shrinking of spin polarons. External magnetic fields shift the ordering transition to lower temperatures according to the field-induced decrease of the carrier localization. The magnetic field -temperature phase boundary line was investigated by means of magnetoresistance (up to 12 T) and pulsed-fields magnetization measurements up to 50 T. The pronounced magnetization anomalies, associated with the phase transition, vanish for fields exceeding 20 T. This behaviour has been attributed to a field-induced crossover from antiferrodistorsive order to a nondistorsive/ferromagnetic orbital configuration. PACS

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“…The magnetoresistivity measurements were carried out at the pulsed field facility of the Katholieke Universiteit Leuven [14,15] by using a homemade flow-cryostat and 50 T coil. All data reported in this paper were obtained on thin films (~150 nm), patterned (1000 x 50 µm strip) for four probe measurements in the transverse geometry (µ 0 H ⊥ I) with the magnetic field perpendicular to the film (µ 0 H // c) and the current sent along the ab-plane (I // ab).…”

Section: Expe Rime Ntal Re Sultsmentioning

confidence: 99%

High field magnetoresistivity of epitaxial La2−xSrxCuO4 thin films

Vanacken

Weckhuysen

Wambecq

et al. 2005

Physica C: Superconductivity and its Applications

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A large positive magnetoresistivity (up to tens of percents) is observed in both underdoped and overdoped superconducting La 2-x Sr x CuO 4 epitaxial thin films at temperatures far above the superconducting critical temperature T c . For the underdoped samples, this magnetoresistance far above T c cannot be described by the Kohler rule and we believe it is to be attributed to the influence of superconducting fluctuations. In the underdoped regime, the large magnetoresistance is only present when at low temperatures superconductivity occurs. T he strong magnetoresistivity, which persists even at temperatures far above T c , can be related to the pairs forming eventually the superconducting state below T c . Our observations support the idea of a close relation between the pseudogap and the superconducting gap and provide new indications for the presence of pairs above T c .

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Experimental techniques for pulsed magnetic fields

Cited by 30 publications

References 9 publications

Compensated electron and hole pockets in an underdoped high-Tcsuperconductor

Compensated electron and hole pockets in an underdoped high-Tcsuperconductor

Influence of the cooperative Jahn-Teller effect on the transport and magnetic properties ofLa7/8Sr1/8<

High field magnetoresistivity of epitaxial La2−xSrxCuO4 thin films

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