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Giant paramagnetic Meissner effect in multiband superconductors.

da Silva RM, Milošević MV, Shanenko AA, Peeters FM, Aguiar JA - Sci Rep (2015)

Bottom Line: Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux.Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate - even multiply larger than the diamagnetic Meissner response for the same applied magnetic field.We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces.

View Article: PubMed Central - PubMed

Affiliation: Programa de Pós-Graduação em Ciência dos Materiais, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n, 50670-901 Recife-PE, Brazil.

ABSTRACT
Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux. In the absence of pinning such paramagnetic response is weak, and ceases with increasing sample thickness. Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate - even multiply larger than the diamagnetic Meissner response for the same applied magnetic field. We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces.

No MeSH data available.


Related in: MedlinePlus

Magnetization M(H) loops at T = 0.94Tc, for sequentially increased ratio of the Fermi velocities v1/v2 (and other parameters λ11 = 1.55, λ22 = 1.3, λ12 = 0.09, n1 = 0.48, and κ1 = 1.5), obtained by sweeping up and down the external magnetic field H (given in units of the thermodynamic critical field Hc).
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f2: Magnetization M(H) loops at T = 0.94Tc, for sequentially increased ratio of the Fermi velocities v1/v2 (and other parameters λ11 = 1.55, λ22 = 1.3, λ12 = 0.09, n1 = 0.48, and κ1 = 1.5), obtained by sweeping up and down the external magnetic field H (given in units of the thermodynamic critical field Hc).

Mentions: In Fig. 2 we show the M(H) loops at T = 0.94Tc, for different values of v1/v2. By increasing the latter parameter, we are actually decreasing the characteristic length scale of the second condensate (since ζ1 is fixed as the unit of distance) and we are thereby driving the system into the Type-II magnetic behavior (since and the GL parameter of the coupled system κ41 are increasing; for calculation of the penetration depth λ, please see Ref. 28). This directly manifests in magnetization curves: for low v1/v2(≲0.3) one easily recognizes typical response of a Type-I slab (see Fig. 2(a)), with superheated Meissner state in increasing field (with subsequent collapse to normal state), and supercooling in decreasing field47, with some flux trapping present; for high v1/v2(≳0.65), the expected response of a Type-II slab is recovered48, still with some paramagnetic flux trapping (see Fig. 2(c)). However, at intermediate values of v1/v2a uniquely different shape of the magnetization loop is found, with a pronounced jump from the Meissner state to the mixed state with increasing field, and a very pronounced paramagnetic response in decreasing field (see Fig. 2(b)).


Giant paramagnetic Meissner effect in multiband superconductors.

da Silva RM, Milošević MV, Shanenko AA, Peeters FM, Aguiar JA - Sci Rep (2015)

Magnetization M(H) loops at T = 0.94Tc, for sequentially increased ratio of the Fermi velocities v1/v2 (and other parameters λ11 = 1.55, λ22 = 1.3, λ12 = 0.09, n1 = 0.48, and κ1 = 1.5), obtained by sweeping up and down the external magnetic field H (given in units of the thermodynamic critical field Hc).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525483&req=5

f2: Magnetization M(H) loops at T = 0.94Tc, for sequentially increased ratio of the Fermi velocities v1/v2 (and other parameters λ11 = 1.55, λ22 = 1.3, λ12 = 0.09, n1 = 0.48, and κ1 = 1.5), obtained by sweeping up and down the external magnetic field H (given in units of the thermodynamic critical field Hc).
Mentions: In Fig. 2 we show the M(H) loops at T = 0.94Tc, for different values of v1/v2. By increasing the latter parameter, we are actually decreasing the characteristic length scale of the second condensate (since ζ1 is fixed as the unit of distance) and we are thereby driving the system into the Type-II magnetic behavior (since and the GL parameter of the coupled system κ41 are increasing; for calculation of the penetration depth λ, please see Ref. 28). This directly manifests in magnetization curves: for low v1/v2(≲0.3) one easily recognizes typical response of a Type-I slab (see Fig. 2(a)), with superheated Meissner state in increasing field (with subsequent collapse to normal state), and supercooling in decreasing field47, with some flux trapping present; for high v1/v2(≳0.65), the expected response of a Type-II slab is recovered48, still with some paramagnetic flux trapping (see Fig. 2(c)). However, at intermediate values of v1/v2a uniquely different shape of the magnetization loop is found, with a pronounced jump from the Meissner state to the mixed state with increasing field, and a very pronounced paramagnetic response in decreasing field (see Fig. 2(b)).

Bottom Line: Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux.Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate - even multiply larger than the diamagnetic Meissner response for the same applied magnetic field.We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces.

View Article: PubMed Central - PubMed

Affiliation: Programa de Pós-Graduação em Ciência dos Materiais, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n, 50670-901 Recife-PE, Brazil.

ABSTRACT
Superconductors, ideally diamagnetic when in the Meissner state, can also exhibit paramagnetic behavior due to trapped magnetic flux. In the absence of pinning such paramagnetic response is weak, and ceases with increasing sample thickness. Here we show that in multiband superconductors paramagnetic response can be observed even in slab geometries, and can be far larger than any previous estimate - even multiply larger than the diamagnetic Meissner response for the same applied magnetic field. We link the appearance of this giant paramagnetic response to the broad crossover between conventional Type-I and Type-II superconductors, where Abrikosov vortices interact non-monotonically and multibody effects become important, causing unique flux configurations and their locking in the presence of surfaces.

No MeSH data available.


Related in: MedlinePlus