Magnetic flux structure on the surface of EuFe2(As1−xPx)2 single crystals with nearly optimal phosphorus doping levels x=0.20, and x=0.21 is studied by low-temperature magnetic force microscopy and decoration with ferromagnetic nanoparticles. The studies are performed in a broad temperature range. It is shown that the single crystal with x=0.21 in the temperature range between the critical temperatures TSC=22 K and TC=17.7 K of the superconducting and ferromagnetic phase transitions, respectively, has the vortex structure of a frozen magnetic flux, typical for type-II superconductors. The magnetic domain structure is observed in the superconducting state below TC. The nature of this structure is discussed.
@article{arxiv.1703.02235,
title = {Visualization of Magnetic Flux Structure in Phosphorus-Doped EuFe$_2$As$_2$ Single Crystals},
author = {I. S. Veshchunov and L. Ya. Vinnikov and V. S. Stolyarov and N. Zhou and Z. X. Shi and X. F. Xu and S. Yu. Grebenchuk and D. S. Baranov and I. A. Golovchanskiy and S. Pyon and Yue Sun and Wenhe Jiao and Guanghan Cao and T. Tamegai and A. A. Golubov},
journal= {arXiv preprint arXiv:1703.02235},
year = {2017}
}