We investigated the effect of Fe segregated from partially Fe-substituted MgO (MgFeO) on the magnetic properties of CoFeB/MgFeO multilayers. X-ray photoelectron spectroscopy (XPS) as well as magnetic measurements revealed that the segregated Fe was reduced to metal and exhibited ferromagnetism at the CoFeB/MgFeO interface. The CoFeB/MgFeO multilayer showed more than 2-fold enhancement in perpendicular magnetic anisotropy (PMA) energy density compared with a standard CoFeB/MgO multilayer. The PMA energy density was further enhanced by inserting an ultrathin MgO layer in between CoFeB and MgFeO layers. Ferromagnetic resonance measurement also revealed a remarkable reduction of magnetic damping in the CoFeB/MgFeO multilayers.
@article{arxiv.2308.08876,
title = {Interfacial Fe segregation and its influence on magnetic properties of CoFeB/MgFeO multilayers},
author = {Tomohiro Ichinose and Tatsuya Yamamoto and Takayuki Nozaki and Kay Yakushiji and Shingo Tamaru and Shinji Yuasa},
journal= {arXiv preprint arXiv:2308.08876},
year = {2023}
}