Evidence for filamentary superconductivity nucleated at antiphase domain walls in antiferromagnetic CaFe$_2$As$_2$

H. Xiao; T. Hu; A. P. Dioguardi; N. apRoberts-Warren; A. C. Shockley; J. Crocker; D. M. Nisson; Z. Viskadourakis; Xianyang Tee; I. Radulov; C. C. Almasan; N. J. Curro; C. Panagopoulos

doi:10.1103/physrevb.85.024530

arXiv · 1107.0904

Evidence for filamentary superconductivity nucleated at antiphase domain walls in antiferromagnetic CaFe$_2$As$_2$

H. Xiao·T. Hu·A. P. Dioguardi·N. apRoberts-Warren·A. C. Shockley·J. Crocker·D. M. Nisson·Z. Viskadourakis·Xianyang Tee·I. Radulov·C. C. Almasan·N. J. Curro·C. Panagopoulos

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Abstract

Resistivity, magnetization and microscopic $^{75}$As nuclear magnetic resonance (NMR) measurements in the antiferromagnetically ordered state of the iron-based superconductor parent material CaFe$_2$As$_2$ exhibit anomalous features that are consistent with the collective freezing of domain walls. Below $T^*\approx 10$ K, the resistivity exhibits a peak and downturn, the bulk magnetization exhibits a sharp increase, and $^{75}$As NMR measurements reveal the presence of slow fluctuations of the hyperfine field. These features in both the charge and spin response are strongly field dependent, are fully suppressed by $H^*\approx 15$ T, and suggest the presence of filamentary superconductivity nucleated at the antiphase domain walls in this material.

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H. Xiao, T. Hu, A. P. Dioguardi, N. apRoberts-Warren, A. C. Shockley, J. Crocker, D. M. Nisson, Z. Viskadourakis, Xianyang Tee, I. Radulov, C. C. Almasan, N. J. Curro, C. Panagopoulos. 2012-01-27. Evidence for filamentary superconductivity nucleated at antiphase domain walls in antiferromagnetic CaFe$_2$As$_2$. https://doi.org/10.1103/physrevb.85.024530

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