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arXiv · 2010.01752

Strong antiferromagnetic proximity coupling in a heterostructured superconductor Sr$_2$VO$_3$FeAs

Jong Mok Ok·Chang Il Kwon·O. E. Ayala Valenzuela·Sunghun Kim·Ross D. McDonald·Jeehoon Kim·E. S. Choi·Woun Kang·Y. J. Jo·C. Kim·E. G. Moon·Y. K. Kim·Jun Sung Kim
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Abstract

We report observation of strong magnetic proximity coupling in a heterostructured superconductor Sr$_2$VO$_3$FeAs, determined by the upper critical fields $H_{c2}(T)$ measurements up to 65 T. Using the resistivity and the radio-frequency measurements for both $H \parallel ab$ and $H \parallel c$, we found a strong upward curvature of $H_{c2}^c(T)$, together with a steep increase of $H_{c2}^{ab}(T)$ near $T_c$, yielding the anisotropic factor $\gamma_H=H_{c2}^{ab}/H_{c2}^c$ up to $\sim$ 20, the largest value among iron-based superconductors. These are attributed to the Jaccarino-Peter effect, rather than to the multiband effect, due to strong exchange interaction between itinerant Fe spins of the FeAs layers and localized V spins of Mott-insulating SrVO$_3$ layers. These findings provide evidence for strong antiferromagnetic proximity coupling, comparable with the intralayer superexchange interaction of SrVO$_3$ layer and sufficient to induce magnetic frustration in Sr$_2$VO$_3$FeAs.

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Jong Mok Ok, Chang Il Kwon, O. E. Ayala Valenzuela, Sunghun Kim, Ross D. McDonald, Jeehoon Kim, E. S. Choi, Woun Kang, Y. J. Jo, C. Kim, E. G. Moon, Y. K. Kim, Jun Sung Kim. 2020-10-05. Strong antiferromagnetic proximity coupling in a heterostructured superconductor Sr$_2$VO$_3$FeAs. https://arxiv.org/abs/2010.01752

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