Nonlocal current-field relation and the vortex-state magnetic properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">YNi</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">B</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:math>

Song, Kyu Jeong; Thompson, James R.; Yethiraj, M.; Christen, D. K.; Tomy, C. V.; Paul, D. Mc K.

doi:10.1103/physrevb.59.r6620

Cited by 27 publications

(25 citation statements)

References 10 publications

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“…The exponential decrease in J c (H) has been reported for other superconducting materials, 33,34 and the J c (H) for the new superconducting Zr 0.96 V 0.04 B 2 compound also shows the exponential decrease. The J c (H) curves over wide temperature regions for the Zr 0.96 V 0.04 B 2 can be well explained by using double exponential model associated with the two superconducting gaps, as shown in Fig.…”

Section: Resultssupporting

confidence: 69%

Critical current density and flux pinning in Zr0.96V0.04B2 superconductor with AlB2 structure

Jung

Vanacken

Moshchalkov

et al. 2013

Journal of Applied Physics

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We have investigated the critical current density (Jc) and the flux pinning behavior in Zr0.96V0.04B2 superconductor with an AlB2 structure. V substitutions in Zr sites of non-superconducting ZrB2 system lead to superconductivity, and the 4% V-substituted Zr0.96V0.04B2 compounds show the highest superconducting transition temperature (Tc) of ∼8.7 K. The magnetic hysteresis (M−H) loops for the Zr0.96V0.04B2 demonstrate type-II superconducting behavior in a broad temperature range, and the Jc is estimated from the M−H loops using the Bean model. The analysis of the double-logarithmic Jc(H) plots indicates the dominance of collective pinning in Zr0.96V0.04B2, and that Jc(H) and magnetic field dependences of the flux pinning force density (Fp) are well fitted by the double exponential model which takes into account the existence of two superconducting gaps.

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Section: Resultssupporting

confidence: 69%

Critical current density and flux pinning in Zr0.96V0.04B2 superconductor with AlB2 structure

Jung

Vanacken

Moshchalkov

et al. 2013

Journal of Applied Physics

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“…For example, although unconventional superconductivity has been suggested as the origin of the square flux-line lattice in Sr 2 RuO 4 , it has nearly two-dimensional metallic properties and a κ-value of only 2.6 [15,50] (and incipient ferromagnetism [51]). We make the general observation that the non-hexagonal structure is well established experimentally in low-κ isotropic metallic materials [7,9], in layered metallic [52] superconductors such as YNi 2 B 2 C [53] and in magnetic superconductors [14][15][16]. It also tends to occur at low temperatures, where one can expect to find strong paramagnetism consistent with the results of this work.…”

Section: Comparison With the Literaturesupporting

confidence: 85%

The non-hexagonal flux-line lattice in superconductors

Hampshire¹

2001

J. Phys.: Condens. Matter

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A generalized form of Ginzburg-Landau theory is proposed which explains the non-hexagonal flux-line lattice found both in metallic and magnetic superconductors without invoking any anisotropic material-dependent properties. The Gibbs energy density postulated for magnetic superconductors (g) is of the form g(B, T ) = α|ψ| 2 + 1 2where M is the total local magnetization, M ions is the local magnetization of the magnetic ions and H ext is the externally applied field strength. The macroscopic Gibbs energy density and magnetization close to the upper critical field have been calculated for all possible periodic flux-line lattice structures, for high and low values of the Ginzburg-Landau constant (κ) in both metallic and magnetic superconductors.The generalized theory is consistent with standard theory for high-κ metallic superconductors. However, for low-κ and/or strongly paramagnetic superconductors for which (1 + χ )/2 < κ 2 < 3.45(1 + χ ) 2 /(1 − χ ) 2 , where χ is the differential susceptibility of the paramagnetic ions in the normal state, non-hexagonal flux-line lattice structures occur. When the flux-line lattice is non-hexagonal,Ferromagnetic and antiferromagnetic superconductivity occur when χ > 1. Furthermore, increasingly strong paramagnetism coexisting with superconductivity can produce a type I-type II phase transition. Experimental evidence for these phenomena and for a correlation between strong paramagnetism in magnetic superconductors and re-entrant superconductivity is discussed.

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“…The nonlocal radius ρ slowly decreases with increasing temperature and is suppressed strongly by scattering. The solid lines are best results from the model calculation where we used the temperature dependence of H 0 and Λ from the literature for YNi 2 B 2 C. 21 Both the local and the non-local models explain the temperature dependence of M at low fields, while only the non-local model can describe the data at and above 35 kOe. The good fit from the nonlocal model is consistent with the equilibrium magnetization analysis of YNi 2 B 2 C, 21 suggesting the importance of nonlocal effects in the magnetization.…”

mentioning

confidence: 99%

Anomalous paramagnetic effects in the mixed state ofLuNi2B2C

et al. 2005

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Anomalous paramagnetic effects in dc magnetization were observed in the mixed state of LuNi2B2C, unlike any reported previously. It appears as a kink-like feature for H ≥ 30 kOe and becomes more prominent with increasing field. A specific heat anomaly at the corresponding temperature suggests that the magnetization anomaly is due to a true bulk transition. A magnetic flux transition from a square to an hexagonal lattice is consistent with the anomaly.In cuprate (high-T c ) superconductors, high-transition temperatures (T c ) and short coherence lengths (ξ) lead to large thermal fluctuation effects, opening a possibility for melting of the flux line lattice (FLL) at temperatures well below the superconducting transition temperature. A discontinuous step in dc magnetization and a sudden, kink-like drop in resistivity signified the first order nature of the melting transition from the vortex lattice into a liquid. 1,2,3 In conventional type II superconductors, with modest transition temperatures and large coherence lengths, vortex melting is also expected to occur in a very limited part of the phase diagram, 4 but it has yet to be observed experimentally. In the rare-earth nickel borocarbides RNi 2 B 2 C (R = Y, Dy, Ho, Er, Tm, Lu), the coherence lengths (ξ ∼ = 10 2Å ) and superconducting transition temperatures (16.1 K for R = Lu) lie between these extremes, suggesting that the vortex melting will be observable and may provide further information on vortex dynamics. Indeed, Mun et al. 5 reported the observation of vortex melting in YNi 2 B 2 C, based on a sharp, kink-like drop in electrical resistivity.Recently, a magnetic field-driven FLL transition has been observed in the tetragonal borocarbides. 6,7,8,9 The transition from square to hexagonal vortex lattice occurs due to the competition between sources of anisotropy and vortex-vortex interactions. The repulsive nature of the vortex interaction favors the hexagonal Abrikosov lattice, whose vortex spacing is larger than that of a square lattice. The competing anisotropy, which favors a square lattice, can be due to lattice effects (fourfold Fermi surface anisotropy), 10 unconventional superconducting order parameter, 11 or an interplay of the two. 12,13 In combination with non-negligible fluctuation effects, the competition leads to unique vortex dynamics right below the H c2 line in the borocarbides, namely a reentrant vortex lattice transition. 9 Fluctuation effects near the upper critical field line wash out the anisotropy effect, stabilizing the Abrikosov hexagonal lattice. 14,15 Here, we report the first observation of paramagnetic effects in the dc magnetization M of the mixed state of LuNi 2 B 2 C. The kink-like feature in M and the corresponding specific heat feature for H ≥ 30 kOe signify the reentrant FLL transition, which is consistent with the low-field FLL transition line inferred from small angle neutron scattering (SANS). 9 Single crystals of LuNi 2 B 2 C were grown in a Ni 2 B flux as described elsewhere 16 and were post-growth annealed at T = 10...

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Nonlocal current-field relation and the vortex-state magnetic properties ofYNi2B2C

Cited by 27 publications

References 10 publications

Critical current density and flux pinning in Zr0.96V0.04B2 superconductor with AlB2 structure

Critical current density and flux pinning in Zr0.96V0.04B2 superconductor with AlB2 structure

The non-hexagonal flux-line lattice in superconductors

Anomalous paramagnetic effects in the mixed state ofLuNi2B2C

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