Paramagnetic Meissner effect and magnetic remanence in granular MgB2

Passos, W. A. C.; Lisboa‐Filho, Paulo Noronha; Fraga, G.L.F.; Fabris, Frederik Wolff; Pureur, P.; Ortiz, W.A.

doi:10.1590/s0103-97332002000400018

Cited by 8 publications

(14 citation statements)

References 5 publications

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“…In addition to high T c cuprates [3][4][5][6][7][8][9][10][11][12], the PME-like attribute is known to occur in a wide variety of other superconductors [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Numerous explanations (see Ref.…”

Section: Introductionmentioning

confidence: 99%

“…The observation of an anomalous paramagnetic magnetization signal (viz., paramagnetic Meissner effect (PME)), instead of the usual diamagnetic behaviour, on field-cooling a superconducting specimen, continues to attract [1,2] attention ever since its discovery [3] in ceramic sample(s) of a high T c cuprate. In addition to high T c cuprates [3][4][5][6][7][8][9][10][11][12], the PME-like attribute is known to occur in a wide variety of other superconductors [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Numerous explanations (see [27] for a review), e.g.…”

Section: Introductionmentioning

confidence: 99%

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Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe₂

Kumar¹,

Tomy²,

Paul³

et al. 2015

J. Phys.: Condens. Matter

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We present here some newer characteristics pertaining to paramagnetic Meissner effect like response in a single crystal of the low Tc superconducting compound 2H-NbSe2 via a detailed study of effects of perturbation on the field-cooled magnetization response. In the temperature range, where an anomalous paramagnetic magnetization occurs, the field-cooled magnetization response is found to be highly metastable: it displays a curious tendency to switch randomly from a given paramagnetic value to a diamagnetic or to a different paramagnetic value, when the system is perturbed by an impulse of an externally applied ac field. The new facets revealed in a single crystal of 2H-NbSe2 surprisingly bear a marked resemblance with the characteristics of magnetization behaviour anticipated for the giant vortex states with multiple flux quanta (LΦ0, Φ0 = hc/2e, L > 1) predicted to occur in mesoscopic-sized superconducting specimen and possible transitions amongst such states.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe₂

Kumar¹,

Tomy²,

Paul³

et al. 2015

J. Phys.: Condens. Matter

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“…When this bulk current exceeds the diamagnetic surface current in the superconductor, the resultant magnetic response becomes paramagnetic. Few superconducting samples, however, exhibit such an effect in the mixed state in the presence of applied fields which can be as high as a few tesla [14][15][16][17][18][19][20][21]. This effect is called the high field paramagnetic effect (HFPME).…”

Section: Introductionmentioning

confidence: 99%

High field paramagnetic effect in the superconducting state of Ti_0.8V_0.2alloy

Matin¹,

Chandra²,

Chattopadhyay³

et al. 2013

Supercond. Sci. Technol.

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We report on the superconducting state of Ti 0.8 V 0.2 alloy, highlighting an anomalous magnetic response in the flux-line lattice or the mixed state. The value of magnetization while cooling down the alloy in the presence of high magnetic field is lower than that obtained while warming it up from the lowest temperature in the presence of the same magnetic field. This is just the opposite to the thermo-magnetic hysteresis observed due to homogeneous flux-line pinning. This anomalous effect appears below a characteristic temperature that shifts towards a lower temperature with the increase in applied magnetic field. The value of magnetization measured at a constant temperature after cooling down the sample in the presence of magnetic field increases appreciably with time in the temperature-field domain where this anomalous effect is observed. These results indicate that the present Ti 0.8 V 0.2 alloy exhibits a high field paramagnetic effect resulting from inhomogeneous flux pinning. Optical metallography and x-ray diffraction measurements show the formation of stress induced martensitic phase in the alloy, which could result in the inhomogeneous flux pinning. The temperature dependence of magnetization after annealing the sample after mechanical processing showed the usual properties of a type-II superconductor. This supports the argument that the inhomogeneous distribution of the stress induced martensitic phase is the reason for the existence of the high field paramagnetic effect in Ti 0.8 V 0.2 alloy.

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“…Furthermore, the paramagnetic-Meissner effect (PME) was proposed as another piece of evidence for the Josephson- junction with the half-flux quantum [100], and was suggested in support of the idea that cuprate superconductors have an order parameter of d-wave symmetry. The PME was observed in BKBO [98], BSCCO [101], YBCO [102], MgB2 [103], and Nb [104,105]. Generally, because a SQUID measuring the PME tends to trap magnetic flux, a trapped SQUID sensor always measures the PME, irrespective of dwave or s-wave type superconductors [98], although a virgin SQUID sensor measures the diamagnetic Meissner effect in a superconductor [98].…”

Section: -3-4 Flux Trap In Squids and Paramagnetic Meissnermentioning

confidence: 99%

High-$T_c$ mechanism through analysis of diverging effective mass for YaBa$_2$Cu$_3$O$_{6+x}$ and pairing symmetry in cuprate superconductors

Kim

2017

Preprint

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In order to clarify the high-Tc mechanism in inhomogeneous cuprate layer superconductors, we deduce and find the correlation strength not revealed before, contributing to the formation of the Cooper pair and the 2-dimensional density of state, and demonstrate the pairing symmetry in the superconductors still controversial. To the open questions, the fitting and analysis of the diverging effective mass with decreasing doping, extracted from the acquired quantum-oscillation data in underdoped YaBa 2 Cu 3 O 6+x superconductors, can provide solutions. In this research, the results of the fitting using the extended Brinkman-Rice(BR) picture reveal the nodal constant Fermi energy with the maximum carrier density, a constant Coulomb correlation strength  BR =U/U c >0.90, and a growing Fermi arc from the nodal Fermi point to the isotropic Fermi surface with an increasing x. The growing of the Fermi arc indicates that a superconducting gap develops with x from the node (underdoped) to the anti-node (optimally or over-doped). The large  BR results from the dx2-y2-wave metal-insulator transition for the pseudogap phase in lightly doped superconductors, which can be direct evidence for high-Tc superconductivity. The quantum critical point is regarded as the nodal Fermi point satisfied with the Brinkman-Rice picture. The experimentally-measured mass diverging behavior is an average effect and the true effective mass is constant. As an application of the nodal constant carrier density, to find a superconducting node gap, the ARPES data and tunneling data are analyzed. The superconducting node gap is a precursor of s-wave symmetry in underdoped cuprates. Furthermore, the halfflux quantum, induced by the circulation of d-wave supercurrent and observed by the phase sensitive Josephson- junction experiments, is not shown due to 'anisotropic or asymmetric effect' appearing in superconductors with trapped flux. The absence of d-wave superconducting pairing symmetry is also revealed.

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Paramagnetic Meissner effect and magnetic remanence in granular MgB2

Cited by 8 publications

References 5 publications

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe₂

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe₂

High field paramagnetic effect in the superconducting state of Ti_0.8V_0.2alloy

High-$T_c$ mechanism through analysis of diverging effective mass for YaBa$_2$Cu$_3$O$_{6+x}$ and pairing symmetry in cuprate superconductors

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Paramagnetic Meissner effect and magnetic remanence in granular MgB2

Cited by 8 publications

References 5 publications

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe2

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe2

High field paramagnetic effect in the superconducting state of Ti0.8V0.2alloy

High-$T_c$ mechanism through analysis of diverging effective mass for YaBa$_2$Cu$_3$O$_{6+x}$ and pairing symmetry in cuprate superconductors

Contact Info

Product

Resources

About

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe₂

Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe₂

High field paramagnetic effect in the superconducting state of Ti_0.8V_0.2alloy