Reversible and irreversible magnetocaloric effect in the NdBa2Cu3O7superconductor in relation to specific heat and magnetization

Plackowski, T.; Wang, Y.; Lortz, Rolf; Junod, A.; Wolf, Th.

doi:10.1088/0953-8984/17/43/007

Cited by 13 publications

(24 citation statements)

References 38 publications

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“…2, the irreversible component M Tគirr enters the magnetocaloric coefficient in the presence of flux pinning and a peak effect very similar to that observed in M is visible for T Ͻ 15 K. The similarity of the irreversible components in both quantities has been discussed in Ref. 15: While the irreversibility in M arises from different vortex density distributions across the sample upon increasing and decreasing the field, the origin of the irreversibility in M T lies in the friction of vortices against pinning centers. Friction can only result in a heat release ␦Q Ͼ 0, irrespective of the direction of the field sweep, thus creating a hysteresis loop between the ascending and descending branches of M T .…”

Section: A Isothermal Magnetizationsupporting

confidence: 55%

“…20 The anomaly has the same shape as observed in M T at the first-order vortex melting transition in ReBa 2 Cu 3 O x ͑Re =Nd,Y͒ compounds. 15,21 Contrary to the irreversible loops at the peak effect, the sign of the spike does not depend on the sign of dB a / dt, confirming that it originates from the reversible thermodynamic contribution M Tគrev . It is therefore most likely to be a signature of the latent heat from a firstorder vortex melting transition, as already discussed in Ref.…”

Section: E Comparison With "Vortex Shaking" Experimentsmentioning

confidence: 87%

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Origin of the magnetization peak effect in theNb3Snsuperconductor

et al. 2007

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We report a pronounced peak effect in the magnetization and the magnetocaloric coefficient in a single crystal of the superconductor Nb 3 Sn. As the origin of the magnetization peak effect in classical type-II superconductors is still strongly debated, we performed an investigation of its underlying thermodynamics. Calorimetric experiments performed during field sweeps at constant temperatures reveal that the sharp increase in the current density occurs concurrently with additional degrees of freedom in the specific heat due to thermal fluctuations and a liquid vortex phase. No latent heat due to a direct first-order melting of a Bragg glass phase into the liquid phase is found, which we take as evidence for an intermediate glass phase with enhanced flux pinning. The Bragg glass phase can, however, be restored by a small ac field. In this case, a first-order vortex melting transition with a clear hysteresis is found. In the absence of an ac field, the intermediate glass phase is located within the field range of this hysteresis. This indicates that the peak effect is associated with the metastability of an underlying first-order vortex melting transition.

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Section: A Isothermal Magnetizationsupporting

confidence: 55%

Section: E Comparison With "Vortex Shaking" Experimentsmentioning

confidence: 87%

Origin of the magnetization peak effect in theNb3Snsuperconductor

et al. 2007

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“…There is considerable evidence that cuprate superconductors with moderate anisotropy exhibit in zero field 3D-xy critical behavior [11,12,13,14,20,22,23,24,36,37,38,39,40,41,42,43,44]. The critical exponents are then given by [45,46] …”

mentioning

confidence: 99%

“…for a NdBa 2 Cu 3 O 7−δ single crystal with Tc = 95.5 K taken from Plackowskiet al [11]. Units are Tesla, Joule/gat and Kelvin.…”

mentioning

confidence: 99%

Magnetic field induced 3D–1D crossover in type-II superconductors

Schneider

2008

J. Phys.: Condens. Matter

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Abstract. We review and analyze magnetization and specific heat investigations on type-II superconductors which uncover remarkable evidence for the magnetic field induced finite size effect and the associated 3D to 1D crossover which enhances thermal fluctuations. Indeed, the correlation length transverse to the magnetic field H i , applied along the i-axis, cannot grow beyond the limiting magnetic length1/2 , related to the average distance between vortex lines. Noting that 1D is incompatible with the occurrence of a continuous phase transition at finite temperatures, the mean-field transition line H C2 (T ) is replaced by the 3D to 1D crossover line Hp (T ). Since the magnetic field induced finite size effect relies on thermal fluctuations and there enhancement originating from the 3D to 1D crossover, its observability is not be restricted to type-II superconductors with small correlation volume only, including YBa 2 Cu 4 O 8 , NdBa 2 Cu 3 O 7−δ , YBa 2 Cu 3 O 7−δ , and DyBa 2 Cu 3 O 7−δ , where 3D-xy critical behavior was already observed in zero field. Indeed, our analysis of the reversible magnetization of RbOs 2 O 6 and the specific heat of Nb 77 Zr 23 , Nb 3 Sn and NbSe 2 reveals that even in these low Tc superconductors with comparatively large correlation volume the 3D to 1D crossover is observable in sufficiently high magnetic fields. Consequently, below Tc and above H pi (T ) superconductivity is confined to cylinders with diameter L H i (1D) and there is no continuous phase transition in the (H, T ) -plane along the H c2 (T ) -line as predicted by the mean-field treatment. Moreover we observe that the thermodynamic vortex melting transition occurs in the 3D regime. While in YBa 2 Cu 4 O 8 , NdBa 2 Cu 3 O 7−δ , YBa 2 Cu 3 O 7−δ , and DyBa 2 Cu 3 O 7−δ it turns out to be driven by 3D-xy thermal fluctuations, the specific heat data of the conventional type-II superconductors Nb 77 Zr 23 , Nb 3 Sn and NbSe 2 point to Gaussian fluctuations. Because the vortex melting and the 3D-1D crossover line occur at universal values of the scaling variable their relationship is universal.

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“…22 More generally, a dissipative process is inevitably involved in the first-order phase transition because of the potential barrier between two phases. In these examples, the magnetization curve also shows irreversibility, namely, hysteresis appears.…”

Section: Introductionmentioning

confidence: 99%

Irreversible Heating Measurement with Microsecond Pulse Magnet: Example of the α–θ Phase Transition of Solid Oxygen

et al. 2016

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Dissipation inevitably occurs in first-order phase transitions, leading to irreversible heating. Conversely, the irreversible heating effect may indicate the occurrence of the first-order phase transition. We measured the temperature change at the magnetic-field-induced α-θ phase transition of solid oxygen. A significant temperature increase from 13 to 37 K, amounting to 700 J/mol, due to irreversible heating was observed at the first-order phase transition. We argue that the hysteresis loss of the magnetization curve and the dissipative structural transformation account for the irreversible heating. The measurement of irreversible heating can be utilized to detect the first-order phase transition in combination with an ultrahigh magnetic fields generated in a time of µs order.

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Reversible and irreversible magnetocaloric effect in the NdBa₂Cu₃O₇superconductor in relation to specific heat and magnetization

Cited by 13 publications

References 38 publications

Origin of the magnetization peak effect in theNb3Snsuperconductor

Origin of the magnetization peak effect in theNb3Snsuperconductor

Magnetic field induced 3D–1D crossover in type-II superconductors

Irreversible Heating Measurement with Microsecond Pulse Magnet: Example of the α–θ Phase Transition of Solid Oxygen

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