We report a study of nano-scale structural peculiarities of the antiferromagnetic layered semimetal EuSn2As2, and show that they are responsible for its puzzling magnetic properties. The high resolution transmission electron microscopy revealed the presence of planar defects in the lattice of the studied single crystals. Using a combination of microstructural and DFT analysis we demonstrated that a single planar nano-defects forms a layer of a distinct phase EuSnAs2, that is different from the EuSn2As2 phase of the bulk lattice. The smaller distance between Eu layers in the planar nano-defect promotes formation of local ferromagnetic (FM) ordering of the Eu atoms. On average, the planar defects form a weak ferromagnetic phase in the antiferromagnetic (AFM) host lattice. The obtained results explain several puzzling features in magnetic properties of A-type AFM materials: the nonlinear magnetization in low in-plane fields, ferromagnetic-type hysteresis in low field, and the upturn of the magnetic susceptibility in the AFM state at temperatures approaching zero.
@article{arxiv.2511.03582,
title = {Emergence of Ferromagnetism from Planar Defects in EuSn2As2 Antiferromagnet},
author = {A. Yu. Levakhova and A. L. Vasiliev and N. S. Pavlov and A. V. Ovcharov and V. I. Bondarenko and A. V. Sadakov and K. S. Pervakov and V. A. Vlasenko and V. M. Pudalov},
journal= {arXiv preprint arXiv:2511.03582},
year = {2025}
}