Wydarzenia w AGH

Referat pt. Tailoring the magnetic anisotropy of antiferromagnetic thin films in epitaxial multilayer systems and ferromagnetic/antiferromagnetic nanostructures wygłosi mgr inż. Hashim Nayyef (Katedra Fizyki Ciała Stałego, WFiIS AGH).

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Streszczenie

X-ray magnetic linear and circular dichroism (XMLD and XMCD) spectroscopy combined with XCMD- and XMLD-PEEM microscopy enabled us to follow the magnetic properties of epitaxial NiO(111)/Fe(110), CoO(111)/Fe(110) and CoO(111)/Au(111)/Fe(110) epitaxial multilayers. We find that in all these three systems ferromagnetic (FM) Fe sublayer plays a dominant role and determines the magnetic state of the neighboring antiferromagnetic (AFM) layer, however different interaction mechanisms are involved. In CoO/Fe bilayers, the AFM spins are fully frozen, and their orientation is imprinted by magnetization of Fe layer when the system passes the Neel temperature of CoO. Once the Fe layer grafts the particular magnetic anisotropy (MA) into the CoO overlayer, it later remains frozen and insensitive to external factors like external magnetic field or Fe magnetization direction [1]. Additionally, the interaction between ferromagnetic Fe(110) and antiferromagnetic CoO(111) sublayers can be mediated and precisely tuned by a nonmagnetic Au spacer[2]. In contrast, for NiO/Fe bilayers we find that due to the weak intrinsic MA of NiO, the NiO spins are rotatable and always follow the reorientation of Fe magnetization that can be controlled by external magnetic field or via the temperature and thickness driven spin reorientation of Fe(110). In the case of the temperature induced spin reorientation transition in Fe(110), it allowed us to implement the field-free switching of AFM moments in NiO/Fe bilayers[3].

[1] M. Ślęzak et al., „Tailorable exchange bias and memory of frozen antiferromagnetic spins in epitaxial CoO(1 1 1)/Fe(1 1 0) bilayers”, J Magn Magn Mater, vol. 545, Mar. 2022, doi: 10.1016/j.jmmm.2021.168783.
[2] H. Nayyef et al., „Tunable interplay between exchange coupling and uniaxial magnetic anisotropy in epitaxial CoO/Au/Fe trilayers”, Sci Rep, vol. 13, no. 1, p. 10902, Jul. 2023, doi: 10.1038/s41598-023-38098-6.
[3] M. Ślȩzak et al., „Controllable magnetic anisotropy and spin orientation of a prototypical easy-plane antiferromagnet on a ferromagnetic suport”, Phys Rev B, vol. 104, no. 13, Oct. 2021, doi: 10.1103/PhysRevB.104.134434.