Panoramics of vortex matter in FeSe and FeSeS at low fields

CORTÉS MALDONADO, RAÚL; FASANO, YANINA; AMIGÓ, MARÍA LOURDES; ARAGÓN SÁNCHEZ, JAZMÍN; NIEVA, GLADYS

Conferencia; Vortex 2021 (18th International Conference in Superconductors - on line); 2021

We apply magnetic decoration to obtain large field-of-view images of the vortex matter nucleatedat the surface of FeSe and FeSeS single crystals at low fields (5-15 Oe). We analyse the structuralproperties in thousands-vortices fields-of-view and found that the non hyperuniform structure iscomposed by a mixture of isotropic and distorted hexagonal domains. Structure factor andDelaunay triangulation analysis indicate that the latter domains correspond to an oblique structureobtained by expanding or compressing the hexagon along the Fe-Fe bond crystallographicdirection (a or b axis). Nevertheless, at the edge of the sample few vortex rows are aligned at 45°from the a and b axis, mimicking the sample geometry.