Observation of Magnetic-Field-Induced Superconductivity

Meul, H.W.; Rossel, C.; Decroux, M.; Fischer, Ø.; Reményi, G.; Briggs, A.

doi:10.1103/physrevlett.53.497

Cited by 163 publications

(99 citation statements)

References 7 publications

(4 reference statements)

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“…Similar phenomena, namely antiferromagnetic, ferromagnetic, or field-induced superconductivity, have been observed in several inorganic solids such as the Chevrel phase 737 and heavy-fermion system. 922 Aiming to combine magnetic and conductive properties within a system, several donor molecules having the coordination ability for paramagnetic transition metals have been proposed.…”

mentioning

confidence: 74%

“…The latter is rather common to organic conductors (i.e., FISDW, see section 3.3.1). In the former case, the reentrant metallic or superconducting phase has been observed on Chevrel compounds 737 or BETS compounds. 610,613 Electric field has also been applied on a Peierls or SDW insulator to depin the density wave, giving rise to a non-linear electric conduction.…”

Section: Band Fillingmentioning

confidence: 99%

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Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

Saito¹,

Yoshida²

2007

Bulletin of the Chemical Society of Japan

367

127

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confidence: 74%

Section: Band Fillingmentioning

confidence: 99%

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

Saito¹,

Yoshida²

2007

Bulletin of the Chemical Society of Japan

367

127

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“…This very general property of superconductors sets strong limits for their practical applications, since, in addition to applied magnetic fields, the current sent through a superconductor also generates magnetic fields, which can lead to a loss of zero resistance. Materials that are not only able to withstand magnetic fields, but in which superconductivity can even be induced by applying a magnetic field, are very rare and up to now only (EuSn)Mo 6 S 8 [1,2], organic λ-(BETS) 2 FeCl 4 materials [4,5] and HoMo 6 S 8 [3] show this unusual behavior. The appearance of magnetic-fieldinduced superconductivity (FIS) in the former two compounds was interpreted in terms of the Jaccarino-Peter effect [6], in which the exchange fields from the paramagnetic ions compensate an applied magnetic field, so that the destructive action of the field is neutralized.…”

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confidence: 99%

Nanoengineered Magnetic-Field-Induced Superconductivity

et al. 2003

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The perpendicular critical fields of a superconducting film have been strongly enhanced by using a nanoengineered lattice of magnetic dots (dipoles) on top of the film. Magnetic-field-induced superconductivity is observed in these hybrid superconductor / ferromagnet systems due to the compensation of the applied field between the dots by the stray field of the dipole array. By switching between different magnetic states of the nanoengineered field compensator, the critical parameters of the superconductor can be effectively controlled. When the applied magnetic field exceeds a certain critical value, superconductivity is suppressed due to orbital and spin pair breaking effects. This very general property of superconductors sets strong limits for their practical applications, since, in addition to applied magnetic fields, the current sent through a superconductor also generates magnetic fields, which can lead to a loss of zero resistance. Materials that are not only able to withstand magnetic fields, but in which superconductivity can even be induced by applying a magnetic field, are very rare and up to now only (EuSn)Mo 6 S 8 [1, 2], organic λ-(BETS) 2 FeCl 4 materials [4,5] and HoMo 6 S 8 [3] show this unusual behavior. The appearance of magnetic-fieldinduced superconductivity (FIS) in the former two compounds was interpreted in terms of the Jaccarino-Peter effect [6], in which the exchange fields from the paramagnetic ions compensate an applied magnetic field, so that the destructive action of the field is neutralized. Here we report that FIS can also be realized in hybrid superconductor / ferromagnet nanostructured bilayers. The basic idea is quite straightforward (see Fig. 1): a lattice of magnetic dots with magnetic moments aligned along the positive z-direction is placed on top of a superconducting film. The magnetic stray field of each dot has a positive z-component of the magnetic induction B z under the dots and a negative one in the area between the dots. Added to a homogeneous magnetic field H, see Fig. 1(b), these dipole fields enhance the z-component of the effective magnetic field µ 0 H ef f = µ 0 H + B z in the small area just under the dots and, at the expense of that, reduce H ef f everywhere else in the Pb film, thus providing the condition necessary for the FIS observation. This new field compensation effect is not restricted to specific superconductors, so that FIS could be achieved in any superconducting film with a lattice of magnetic dots. To implement the idea of the nanoengineered FIS, we have prepared a sample, which reminds us of other systems used during the last decade for studying flux pinning by periodic arrays of magnetic dots

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“…The effect can also be observed in a paramagnet since the strong external field will in any case polarize the localized magnetic moments at low temperature, and thus produce the necessary ferromagnetic alignment [18].Therefore, superconductivity can occur in two domains: one at the low field, where the pair-breaking field is still small, and one at the high field in the compensation region. The field reentrance of superconductivity was first reported in [19,20].The JP compensation mechanism was originally proposed to explain the superconductivity in some pseudoternary materials. Recently, the JP effect has been proven to be responsible for the magnetic-field-induced superconductivity in the organic superconductor λ − (BET S) 2 F eCl 4 [21,22].…”

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confidence: 99%

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confidence: 99%

Coexistence of superconductivity and magnetism in spin-fermion model of ferrimagnetic spinel in an external magnetic field

Karchev

2015

EPL

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A two-sublattice spin-fermion model of ferrimagnetic spinel, with spin-1/2 itinerant electrons at the sublattice A site and spin-s localized electrons at the sublattice B site is considered. The exchange between itinerant and localized electrons is antiferromanetic. As a result the external magnetic field, applied along the magnetization of the localized electrons, compensates the Zeeman splitting due to the spin-fermion exchange and magnon-fermion interaction induces spin anti-parallel p-wave superconductivity which coexists with magnetism. We have obtained five characteristic values of the applied field (in units of energy) Hcr1 < H3 < H0 < H4 < Hcr2. At H0 the external magnetic field compensates the Zeeman splitting. When Hcr1 < H < Hcr2 the spin antiparallel p-wave superconductivity with T1u configuration coexists with magnetism. The superconductor to normal magnet transition at finite temperature is second order when H runs the interval (H3, H4). It is an abrupt transition when Hcr1 < H < H3 or H4 < H < Hcr2. This is proved calculating the temperature dependence of the gap for three different values of the external magnetic field Hcr1 < H < H3, H4 < H < Hcr2 and H = H0. In the first two cases the abrupt fall to zero of the gap at superconducting critical temperature shows that the superconductor to normal magnet transition is first order. The Hubbard term (Coulomb repulsion), in a weak coupling regime, does not affect significantly the magnon induced superconductivity. Relying on the above results one can formulate a recipe for preparing a superconductor from ferrimagnetic spinel: i) hydrostatic pressure above the critical value of insulator-metal transition. ii) external magnetic field along the sublattice magnetization with higher amplitude.PACS numbers: 75.50. Gg,74.20.Mn,74.20.Rp Electron-phonon mechanism of superconductivity [1-4] has been developed to explain the pairing in a large variety of materials, from Hg and Al to recently discovered M gB 2 [5]. The discovery of superconductivity in LaBaCuO [6] and in other cuprates, as well as discovery of superconductivity in F e-based pnictides [7] established another direction of research in this field. The bosonfermion models still remained respected but bosons are not lattice vibrations.Alternatively, the possibility of an electronic pairing mechanism in systems with rotational invariance was put forward in a seminal paper by . Although the bare interaction among electrons is repulsive, there is an effective attractive interaction that arise at higher order of perturbation theory. The KohnLuttinger instability of a three-dimensional rotationally invariant system results in the formation of a unconventional superconducting ground state due to the peak in the particle-hole susceptibility near zero wave vector. The works [11][12][13][14][15] have made significant progress in our understanding of superconductivity from repulsive interaction.There are many experiments addressing external magnetic field induced, enhanced or reentered superconductivity. Expe...

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Observation of Magnetic-Field-Induced Superconductivity

Cited by 163 publications

References 7 publications

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

Nanoengineered Magnetic-Field-Induced Superconductivity

Coexistence of superconductivity and magnetism in spin-fermion model of ferrimagnetic spinel in an external magnetic field

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