3 years ago

# Plastic pinning replaces collective pinning as the second magnetization peak disappears in the pnictide superconductor Ba-KFe$_2$As$_2$.

Hai-Hu Wen, L.F. Cohen, H. S. Amorim, S. Salem-Sugui Jr., K. A. Yates, Shyam Sundar, L. Ghivelder

We report a detailed study of isofield magnetic relaxation and isothermal magnetization measurements with $H$\parallel$c on an underdoped Ba$_{0.75}$K$_{0.25}$Fe$_2$As$_2$pnictide single crystal, with superconducting transition temperature$T_c$= 28 K. The second magnetization peak (SMP) has been observed at temperatures below$T_c$/2 and vanished at higher temperatures. The observed behaviour of the SMP has been studied by measuring the magnetic field dependence of relaxation rate,$R(H)$and by performing the Maley's analysis. The results suggest that the crossover from collective to plastic pinning observed in the SMP disappears above 12 K with plastic pinning replacing collective pinning. An interesting$H$-$T$phase diagram is obtained. The critical current density ($J_c$) was estimated using Bean's model and found to be$\sim3.4 \times 10^9$A/m$^2$at 10 K in the SMP region, which is comparable to an optimally doped Ba-KFe$_2$As$_2$superconductor and may be exploited for potential technological applications. The pinning mechanism is found to be unconventional and does not follow the usual$\delta l$and$\delta T_c\$ pinning models, which suggest the intrinsic nature of pinning in the compound.

Publisher URL: http://arxiv.org/abs/1801.04972

DOI: arXiv:1801.04972v1

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.