Comparative study of vortex dynamics in CaKFe4As4 and Ba0.6K0.4Fe2As2 single crystals

Wang, Cheng; Lin, Hai; Shen, Bing; Wen, Hao

doi:10.1016/j.scib.2018.12.024

Cited by 34 publications

(30 citation statements)

References 49 publications

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“…On the other hand, because of thermally activated vortex motion, J c data usually decrease with temperature. An exception to that has been recently observed in CaKFe 4 As 4 single crystals [16,17,22,23]. For instance, as a consequence of smoother J c (H ) dependences, the J c value for μ 0 H = 5 T at 20 K is higher than that observed at 10 K. This unusual behavior has been related to the presence of planar CaFe 2 As 2 intergrowths [16].…”

Section: Introductionmentioning

confidence: 64%

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Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)
Haberkorn
¹
,
Xu
²
,
Meier
³

et al. 2019
Phys. Rev. B
16
4
29
0
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We study the correlation between chemical composition and vortex dynamics in Ni-doped CaK(Fe1−xNix)4As4 (x=0, 0.015, 0.025, 0.03, and 0.05) single crystals by performing measurements of the critical current densities Jc and the flux creep rates S. The magnetic relaxation of all the crystals is well described by the collective creep theory. The samples display a glassy exponent μ within the predictions for vortex bundles in a weak pinning scenario and relatively small characteristic pinning energy (U0<100K). The undoped crystals display modest Jc values at low temperatures and high magnetic fields applied along the c axis. Jc(T) dependences at high fields display an unusual peak. The enhancement in Jc(T) matches with an increase in U0 and the appearance of a second peak in the magnetization. As Ni doping increases, whereas there is a monotonic decrease in Tc there is a nonmonotonic change in Jc. Initially Jc increases, reaching a maximum value for x=0.015, and then Jc decreases for x≥0.025. This change in Jc(x) is coincident with the onset of antiferromagnetic order. The magnetic field dependence of Jc(H) also manifests a change in behavior between these x values. The analysis of the vortex dynamics for small and intermediate magnetic fields shows a gradual evolution in the glassy exponent μ with Ni content, x. This implies that there is no appreciable change in the mechanism that determines the vortex relaxation.We study the correlation between chemical composition and vortex dynamics in Ni-doped CaK(Fe 1−x Ni x ) 4 As 4 (x = 0, 0.015, 0.025, 0.03, and 0.05) single crystals by performing measurements of the critical current densities J c and the flux creep rates S. The magnetic relaxation of all the crystals is well described by the collective creep theory. The samples display a glassy exponent μ within the predictions for vortex bundles in a weak pinning scenario and relatively small characteristic pinning energy (U 0 < 100 K). The undoped crystals display modest J c values at low temperatures and high magnetic fields applied along the c axis. J c (T ) dependences at high fields display an unusual peak. The enhancement in J c (T ) matches with an increase in U 0 and the appearance of a second peak in the magnetization. As Ni doping increases, whereas there is a monotonic decrease in T c there is a nonmonotonic change in J c . Initially J c increases, reaching a maximum value for x = 0.015, and then J c decreases for x 0.025. This change in J c (x) is coincident with the onset of antiferromagnetic order. The magnetic field dependence of J c (H ) also manifests a change in behavior between these x values. The analysis of the vortex dynamics for small and intermediate magnetic fields shows a gradual evolution in the glassy exponent μ with Ni content, x. This implies that there is no appreciable change in the mechanism that determines the vortex relaxation. EFFECT OF Ni DOPING ON VORTEX PINNING IN … PHYSICAL REVIEW B 100, 064524 (2019) FIG. 2. (a)-(e) Magnetic field dependence of the critical current densities J c a...

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Section: Introductionmentioning

confidence: 64%

“…The undoped crystals display an unusual maximum at J c (T ) at intermediate temperatures [see Fig. 2(a)] [16,17,22,23]. The effect 064524-3 disappears for Ni-doped samples.…”

Section: Resultsmentioning

confidence: 99%

Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)
Haberkorn
¹
,
Xu
²
,
Meier
³

et al. 2019
Phys. Rev. B
16
4
29
0
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“…In fact, recent studies on vortex pinning properties of CaK1144 reported unusually high Jc 30 as well as vortex dynamics distinct from 122 materials, 31 while the relevant pinning mechanisms remain unsolved. This motivated us to explore the microstructure and the vortex pinning mechanisms in CaK1144.…”

Section: Introductionmentioning

confidence: 99%

Unique defect structure and advantageous vortex pinning properties in superconducting CaKFe4As4

et al. 2019

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The lossless current-carrying capacity of a superconductor is limited by its critical current density (Jc). A key to enhance Jc towards real-life applications is engineering defect structures to optimize the pinning landscape. For iron-based superconductors (IBSs) considered as candidate materials for high-field applications, high Jc values have been achieved by various techniques to introduce artificial pinning centres. Here we report extraordinary vortex pinning properties in CaKFe4As4 (CaK1144) arising from the inherent defect structure. Scanning transmission electron microscopy revealed the existence of nanoscale intergrowths of the CaFe2As2 phase, which is unique to CaK1144 formed as a line compound. The Jc properties in CaK1144 are found to be distinct from other IBSs characterized by a significant anisotropy with respect to the magnetic field orientation as well as a remarkable pinning mechanism significantly enhanced with increasing temperature. We propose a comprehensive explanation of the Jc properties based on the unique intergrowths acting as pinning centres.

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“…CaK-1144 单晶在 H//c 不同磁场(0.5~6 T)下 J c 的温度依赖性 [33] . (c) CaK-1144 单晶在 bc 面以及 ab 面内的扫描透射电子显微镜(STEM)图像，其中插图为 bc 面内的高倍数放大图 [34] Figure CaK-1144 and BaK-122 single crystal in different field directions are also listed [32] .…”

Section: 单晶的生长unclassified

“…Temperature dependence of J c for CaK-1144 single crystal under H//c at 0.5-6 T [33] . (c) STEM images of CaK-1144 single crystal on the bc plane and ab plane, the inset is the higher magnification images on the bc plane [34] 针对 CaK-1144 中特殊的钉扎机制，即与 BaK-122 不同的 J c //c -T 以及 J c 的各向异性， Ishida 和 Pyon 等人 [32,34] 提出了解释，即 CaK-1144…”

Section: 单晶的生长mentioning

confidence: 99%

1144-type iron-based superconducting materials: Status and prospect

Cheng¹,

Zhang²,

Dong³

et al. 2021

Chin. Sci. Bull.

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Comparative study of vortex dynamics in CaKFe4As4 and Ba0.6K0.4Fe2As2 single crystals

Cited by 34 publications

References 49 publications

Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)
Haberkorn
¹
,
Xu
²
,
Meier
³

et al. 2019
Phys. Rev. B
16
4
29
0
View full text Add to dashboard Cite

Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)
Haberkorn
¹
,
Xu
²
,
Meier
³

et al. 2019
Phys. Rev. B
16
4
29
0
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Unique defect structure and advantageous vortex pinning properties in superconducting CaKFe4As4

1144-type iron-based superconducting materials: Status and prospect

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Comparative study of vortex dynamics in CaKFe4As4 and Ba0.6K0.4Fe2As2 single crystals

Cited by 34 publications

References 49 publications

Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)Haberkorn1, Xu2, Meier3 et al. 2019Phys. Rev. B164290View full textAdd to dashboardCite

Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)Haberkorn1, Xu2, Meier3 et al. 2019Phys. Rev. B164290View full textAdd to dashboardCite

Unique defect structure and advantageous vortex pinning properties in superconducting CaKFe4As4

1144-type iron-based superconducting materials: Status and prospect

Contact Info

Product

Resources

About

Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)
Haberkorn
¹
,
Xu
²
,
Meier
³

et al. 2019
Phys. Rev. B
16
4
29
0
View full text Add to dashboard Cite

Effect of Ni doping on vortex pinning in CaK(Fe1−xNix)
Haberkorn
¹
,
Xu
²
,
Meier
³

et al. 2019
Phys. Rev. B
16
4
29
0
View full text Add to dashboard Cite