Density-gradient mechanism of vortex plastic creep

Burlachkov, L.; Vinokur, V. M.

doi:10.1103/physrevb.106.094513

Cited by 2 publications

(5 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The clear difference in the behavior observed on the U ( M ) curves as H crosses the SMP is characteristic of a pinning crossover. Figure 4 b shows that each different set of U ( M ) appearing in the top panels can be scaled as with n = 1.2 for H below and n = − 1 for H above , in agreement with the behavior expected for an elastic pinning (collective) to plastic pinning crossover 45 , 67 . Figure 4 c shows U ( M ) curves calculated with C = 14 obtained from the M ( t ) curves for selected field values lying below and above the peak field , on the M ( H ) at 20 K for -planes.…”

Section: Resultssupporting

confidence: 72%

“…4 c follows the same scaling behavior, but with an exponent n = − 0.5 above and n = − 0.1 below . The exponent n = − 0.5 obtained above is close to the one expected for plastic pinning, while the exponent n = − 0.1 obtained below is too small, but shows the same trend with H associated to plastic pinning 45 , 67 . The increase of magnetization with increasing field, observed below , is not expected to be compatible with plasticity, therefore it is likely that some other vortex pinning mechanism associated with plasticity produces the increase of magnetization with field.…”

Section: Resultssupporting

confidence: 66%

See 1 more Smart Citation

Second magnetization peak, anomalous field penetration, and Josephson vortices in KCa$$_2$$Fe$$_4$$As$$_4$$F$$_2$$ bilayer pnictide superconductor

Lopes

Sundar

Salem‐Sugui

et al. 2022

Sci Rep

View full text Add to dashboard Cite

We performed magnetization measurements in a single crystal of the anisotropic bilayer pnictide superconductor KCa$$_2$$ 2 Fe$$_4$$ 4 As$$_4$$ 4 F$$_2$$ 2 , with $$T_c\;$$ T c $$\simeq$$ ≃ 34 K, for $$H$$ H $$\parallel$$ ‖ $$c$$ c -axis and $$H$$ H $$\parallel$$ ‖ $$ab$$ ab -planes. A second magnetization peak (SMP) was observed in the isothermal M(H) curves measured below 16 K for $$H$$ H $$\parallel$$ ‖ $$ab$$ ab -planes. A peak in the temperature variation of the critical current density, $$J_{c}$$ J c (T), at 16 K, strongly suggests the emergence of Josephson vortices at lower temperatures, which leads to the SMP in the sample. In addition, it is noticed that the appearance of Josephson vortices below 16 K renders easy magnetic flux penetration. A detailed vortex dynamics study suggests that the SMP can be explained in terms of elastic pinning to plastic pinning crossover. Furthermore, contrary to the common understanding, the temperature variation of the first peak field, $$H_1$$ H 1 , below and above 16 K, behaves non-monotonically. A highly disordered vortex phase, governed by plastic pinning, has been observed between 17 and 23 K, within a field region around an extremely large first peak field. Pinning force scaling suggests that the point defects are the dominant source of pinning for H$$\parallel$$ ‖ $$ab$$ ab -planes, whereas, for H $$\parallel$$ ‖ $$c$$ c -axis, point defects in addition to surface defects are at play. Such disorder contributes to the pinning due to the variation in charge carrier mean free path, $$\delta l$$ δ l -pinning. Moreover, the large $$J_c$$ J c observed in our study is consistent with the literature, which advocates this material for high magnetic field applications.

show abstract

Section: Resultssupporting

confidence: 72%

Section: Resultssupporting

confidence: 66%

Second magnetization peak, anomalous field penetration, and Josephson vortices in KCa$$_2$$Fe$$_4$$As$$_4$$F$$_2$$ bilayer pnictide superconductor

Lopes

Sundar

Salem‐Sugui

et al. 2022

Sci Rep

View full text Add to dashboard Cite

show abstract

“…This suggests a change in the size of the vortex bundles in elastic creep from large bundles at low temperature side to medium size bundles of 3D vortices at high temperatures. On the non-glassiness side, p , and were obtained for 5 kOe, 10 kOe and 20 kOe respectively, where, except for 20 kOe, the p values agree reasonably with the density-gradient mechanism of plastic vortex-creep 45 . However, large value of p for 20 kOe, does not support the existing mechanism of plastic vortex-creep, and therefore, it might be a representative of the entangled vortex phase at high magnetic fields that may likely have a different mechanism of vortex-creep.…”

Section: Resultsmentioning

confidence: 52%

“…For H c , 1.5(1) is observed for magnetic field range of 3–20 kOe, which suggests the elastic creep of small bundles of 3D vortices, whereas, in the non-glassiness side, 1, for magnetic field range 3–10 kOe, suggest more than one mechanisms of vortex-creep. However, p 0.6, indicates the density-gradient mechanism of plastic vortex-creep for 20 kOe 45 . For H ab (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, in the case of non-glassiness, U ( J ) suppresses with J , the exponent is defined as p <0. In a recent theoretical development, p = − 0.75 is predicted for the plastic vortex-creep mediated by the mobility of edge dislocation through the vortex-density gradient 45 . It is to note that such plasticity is different than the one usually observed in atomic solids and is unique to the vortex state in a superconductor.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Order–disorder phase transition and elastic-to-plastic vortex creep crossover in a triclinic iron pnictide superconductor (Ca$$_{0.85}$$La$$_{0.15}$$)$$_{10}$$(Pt$$_3$$As$$_8$$)(Fe$$_2$$As$$_2$$)$$_5$$

Sundar,

Lopes,

Salem-Sugui

et al. 2023

Sci Rep

View full text Add to dashboard Cite

Vortex matter in layered high-$$T_c$$ T c superconductors, including iron-pnictides, undergo several thermodynamic phase transitions due to the complex interplay of pinning energy, thermal energy and elastic energy. Moreover, the presence of anisotropy makes their vortex physics even more intriguing. Here, we report a detailed vortex dynamics study, using dc magnetization measurements, in a triclinic iron-pnictide superconductor (Ca$$_{0.85}$$ 0.85 La$$_{0.15}$$ 0.15 )$$_{10}$$ 10 (Pt$$_3$$ 3 As$$_8$$ 8 )(Fe$$_2$$ 2 As$$_2$$ 2 )$$_5$$ 5 , with a superconducting transition temperature, T$$_c$$ c $$\sim$$ ∼ 31 K. A second magnetization peak (SMP) feature is observed for magnetic field perpendicular (H$$\parallel$$ ‖ c) and parallel (H$$\parallel$$ ‖ ab) to the crystal plane. However, its fundamental origin is quite different in both directions. For H$$\parallel$$ ‖ c, the SMP can be well explained using an elastic-to-plastic vortex creep crossover, using collective creep theory. In addition, a possible rhombic-to-square vortex lattice phase transition is also observed for fields in between the onset-field and peak-field related to the SMP. On the other hand, for H$$\parallel$$ ‖ ab, a clear signature of an order-disorder vortex phase transition is observed in the isothermal M(H) measurements at T$$\ge$$ ≥ 6 K. The disordered phase exhibits the characteristics of entangled pinned vortex-liquid. We construct a comprehensive vortex phase diagram by displaying characteristic temperatures and magnetic fields for both crystal geometries in this unique superconducting compound. Our study sheds light on the intricate vortex dynamics and pinning in an iron-pnictide superconductor with triclinic symmetry.

show abstract

Density-gradient mechanism of vortex plastic creep

Cited by 2 publications

References 39 publications

Second magnetization peak, anomalous field penetration, and Josephson vortices in KCa$$_2$$Fe$$_4$$As$$_4$$F$$_2$$ bilayer pnictide superconductor

Second magnetization peak, anomalous field penetration, and Josephson vortices in KCa$$_2$$Fe$$_4$$As$$_4$$F$$_2$$ bilayer pnictide superconductor

Order–disorder phase transition and elastic-to-plastic vortex creep crossover in a triclinic iron pnictide superconductor (Ca$$_{0.85}$$La$$_{0.15}$$)$$_{10}$$(Pt$$_3$$As$$_8$$)(Fe$$_2$$As$$_2$$)$$_5$$

Contact Info

Product

Resources

About