The magnetic properties of thin-film multilayers [Fe/Py]/FeMn/Py are investigated as a function of temperature and thickness of the antiferromagnetic FeMn spacer using SQUID magnetometry. The observed behavior differs substantially for the structures with 6-nm and 15-nm FeMn spacers. While the 15-nm-FeMn structure exhibits exchange pinning of both ferromagnetic layers in the entire measurement temperature interval from 5 to 300 K, the 6-nm-FeMn structure becomes exchange de-pinned in the vicinity of room temperature. The de-pinned state is characterized by a single hysteresis loop centered around zero field and having enhanced magnetic coercivity. The observed properties are explained in terms of finite-size effects and possibly ferromagnetic interlayer coupling through the thin antiferromagnetic spacer.
@article{arxiv.2104.06146,
title = {Temperature and thickness dependent magnetostatic properties of [Fe/Py]/FeMn/Py multilayers},
author = {D. M. Polishchuk and O. I. Nakonechna and Ya. M. Lytvynenko and V. Kuncser and Yu. O. Savina and V. O. Pashchenko and A. F. Kravets and A. I. Tovstolytkin and V. Korenivski},
journal= {arXiv preprint arXiv:2104.06146},
year = {2021}
}