An investigation of the appearance of positive magnetic moments on field cooling some superconductors

Blunt, F.J.; Perry, Abigail R.; Campbell, A.M.; Siu, R.S.

doi:10.1016/0921-4534(91)90262-w

Cited by 52 publications

(14 citation statements)

References 2 publications

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“…The result presented in figure 6 is similar to an observation made by Blunt et al 36 , when they investigated the origin of "paramagnetic" moments in the superconducting state of In view of the observed sensitivity of the Ru-1212 measured magnetization to field inhomogenieties and since we have no evidence that a field reversal, similar to that for the measurements presented in figure 6, or cycling of the magnet, similar to that before the measurements presented in figure 7, affect the field profile of the superconducting magnet in a systematic way, we consider measurements similar to those in figure 8b as the most reliable test, that helps to decide, whether the observed features in a SQUID magnetization measurement of Ru-1212 (or any other superconductor) represent a true property of the compound or not.…”

Section: The Real Origin Of the Ru-1212 Magnetization Peakssupporting

confidence: 82%

SuperconductingRuSr2GdCu2O8
Papageorgiou
¹
,
Braun
²
,
Herrmannsdörfer
³

2002
Phys. Rev. B
17
3
17
0
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For polycrystalline RuSr 2 GdCu 2 O 8 (Ru-1212), distinct peaks have been reported in d.c. magnetization in the superconducting state of the sample. Sr 2 GdRuO 6 (Sr-2116), the precursor for the preparation of Ru-1212, shows similar peaks in the same temperature regime. Based on measurements performed on both bulk and powdered samples of Ru-1212 and Sr-2116, we exclude the possibility, that the observed behavior of the magnetization of Ru-1212 is due to Sr-2116 impurities. The effect is related to the superconductivity of Ru-1212, but it is not an intrinsic property of this compound. We provide evidence that the observation of magnetization peaks in the superconducting state of Ru-1212 is due to flux motion generated by the movement of the sample in an inhomogeneous field, during the measurement in the SQUID magnetometer. We propose several tests, that help to decide, whether the features observed in a SQUID magnetization measurement of Ru-1212 represent a property of the compound or not.

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Section: The Real Origin Of the Ru-1212 Magnetization Peakssupporting

confidence: 82%

SuperconductingRuSr2GdCu2O8
Papageorgiou
¹
,
Braun
²
,
Herrmannsdörfer
³

2002
Phys. Rev. B
17
3
17
0
View full text Add to dashboard Cite

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“…For example, at B a = 1 T for A = 4 mm δ 1.2 × 10 −7 m, which results in the nonuniformity of the magnetic field of ∼δ/(l/2) ∼ 5 × 10 −5 . This estimation is well consistent with previous estimations of nonuniformity of the magnetic fields in MPMS sample space [52,53], which can induce the so-called paramagnetic Meissner effect [52,54].…”

Section: Phenomenological Model For Flux-jumps In Nb Filmssupporting

confidence: 92%

Origin of magnetic flux-jumps in Nb films subject to mechanical vibrations and corresponding magnetic perturbations

et al. 2018

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In this paper the origin of flux-jumps in Nb thin films is established during magnetization measurements using a vibrating sample magnetometer (VSM). Magnetization measurements of the flux avalanche activity show its strong dependence on frequency and amplitude of VSM vibration. In particular, under certain conditions the vibrations induce a transition from a stable superconducting critical state to an undercritical state, accompanied by the 20-fold drop in the magnetic moment. These features allow the elucidation of the origin of the flux-jumps. In contrast to the commonly assumed thermomagnetic instabilities to be responsible for the flux-jumps in Nb films, our results provide solid support for an alternative explanation being due to criticalitybuilt instability well represented by a sandpile. Considering properties of the flux-flow during a flux avalanche regime allows us to estimate nonuniformity of a magnetic field in a VSM sample space developed as a result of vibrations.

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“…In Ref. 63, the level of such inhomogeneities in MPMS was investigated. It was shown that such inhomogeneities caused positive signal below T c upon field cooled magnetization measurements as a function of temperature, the so-called paramagnetic Meissner effect (PME).…”

Section: The Origin Of Vibration-induced Phenomenamentioning

confidence: 99%

Rectifying differences in transport, dynamic, and quasi-equilibrium measurements of critical current density

Golovchanskiy

Pan

Shcherbakova

et al. 2013

Journal of Applied Physics

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Golovchanskiy, I. A., Pan, A. V., Shcherbakova, O. V. & Fedoseev, S. A. (2013). Rectifying differences in transport, dynamic, and quasiequilibrium measurements of critical current density. Journal of Applied Physics, 114 (16), 163910-1-163910-9.Rectifying differences in transport, dynamic, and quasi-equilibrium measurements of critical current density AbstractThe dependence of the critical current density ( J c ) on electric field criteria (E cr ) is studied for high-quality YBCO (YBa 2 Cu 3 O 7 ) thin films over the entire applied magnetic field (B a ) range. The quantitative model describing the J c (B a ) dependence is compared and explained for the critical current densities obtained by different measurement techniques. Transport current and quasi-equilibrium magnetization measurement data can successfully be fitted by the model with appropriate electric field criteria. The dependence of the irreversibility field on the E cr criterion can be obtained within the model. At the same time, the dynamic magnetization measurements of the J c (B a ) curves strongly depend on instrumentally defined parameters, introducing inconsistencies in the experimental results. Therefore, the model calculations are able to explain the J c (B a ) curves only if the instrumental vibrations affecting vortex behaviour are taken into account. However, the nature of the observed dependence on the vibration of the samples is unclear. Different frequencies of the sample vibrations have been investigated. It is revealed that if the frequency tends to zero, the J c (B a ) curves are well described by the model. We have outlined a number of possibilities which may be responsible for the behaviour observed. However, none of the existing theories can explain the effect of the vibrations, which exponentially degrade the irreversibility field to a certain tampered B irr value at frequencies larger than ≃25 Hz . Rectifying differences in transport, dynamic, and quasi-equilibrium measurements of critical current density The dependence of the critical current density (J c ) on electric field criteria (E cr ) is studied for high-quality YBCO (YBa 2 Cu 3 O 7 ) thin films over the entire applied magnetic field (B a ) range. The quantitative model describing the J c ðB a Þ dependence is compared and explained for the critical current densities obtained by different measurement techniques. Transport current and quasi-equilibrium magnetization measurement data can successfully be fitted by the model with appropriate electric field criteria. The dependence of the irreversibility field on the E cr criterion can be obtained within the model. At the same time, the dynamic magnetization measurements of the J c ðB a Þ curves strongly depend on instrumentally defined parameters, introducing inconsistencies in the experimental results. Therefore, the model calculations are able to explain the J c ðB a Þ curves only if the instrumental vibrations affecting vortex behaviour are taken into account. However, the nature of the observed dependence on the vibration o...

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An investigation of the appearance of positive magnetic moments on field cooling some superconductors

Cited by 52 publications

References 2 publications

SuperconductingRuSr2GdCu2O8
Papageorgiou
¹
,
Braun
²
,
Herrmannsdörfer
³

2002
Phys. Rev. B
17
3
17
0
View full text Add to dashboard Cite

SuperconductingRuSr2GdCu2O8
Papageorgiou
¹
,
Braun
²
,
Herrmannsdörfer
³

2002
Phys. Rev. B
17
3
17
0
View full text Add to dashboard Cite

Origin of magnetic flux-jumps in Nb films subject to mechanical vibrations and corresponding magnetic perturbations

Rectifying differences in transport, dynamic, and quasi-equilibrium measurements of critical current density

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An investigation of the appearance of positive magnetic moments on field cooling some superconductors

Cited by 52 publications

References 2 publications

SuperconductingRuSr2GdCu2O8Papageorgiou1, Braun2, Herrmannsdörfer3 2002Phys. Rev. B173170View full textAdd to dashboardCite

SuperconductingRuSr2GdCu2O8Papageorgiou1, Braun2, Herrmannsdörfer3 2002Phys. Rev. B173170View full textAdd to dashboardCite

Origin of magnetic flux-jumps in Nb films subject to mechanical vibrations and corresponding magnetic perturbations

Rectifying differences in transport, dynamic, and quasi-equilibrium measurements of critical current density

Contact Info

Product

Resources

About

SuperconductingRuSr2GdCu2O8
Papageorgiou
¹
,
Braun
²
,
Herrmannsdörfer
³

2002
Phys. Rev. B
17
3
17
0
View full text Add to dashboard Cite

SuperconductingRuSr2GdCu2O8
Papageorgiou
¹
,
Braun
²
,
Herrmannsdörfer
³

2002
Phys. Rev. B
17
3
17
0
View full text Add to dashboard Cite