In-plane spin reorientation transition in Fe/NiO bilayers on Ag(1,1,10)

Abstract

Magnetic properties of Fe/NiO bilayers grown on a (1,1,10) vicinal surface of Ag(001) were studied by magneto-optical Kerr effect (MOKE) and x-ray magnetic linear dichroism (XMLD). The orientation of the antiferromagnetically (AFM) aligned spins of NiO films shows an in-plane spin-reorientation transition (SRT) from parallel to perpendicular to the steps with increasing NiO thickness. Two in-plane SRTs of Fe moments are found in dependence of the NiO thickness. The first SRT of the Fe magnetization from parallel to perpendicular to the steps is observed at NiO thickness where antiferromagnetic order is found, the second at the NiO thickness of the SRT in the NiO film. Also, the in-plane SRT of Fe spins driven by a temperature increase is observed. The perpendicular coupling between the Fe and NiO spins is proven. The induced uniaxial anisotropy energy is estimated to be 0.12 erg/cm 2 .

Effect of CoO/Ni orthogonal exchange coupling on perpendicular anisotropy of Ni films on Pd(001)

“…Theoretically, it is well known that such an orthogonal coupling can generate an effective uniaxial anisotropy [19]. This has been observed experimentally for many FM systems with in-plane anisotropy, for instance, NiO/Fe or CoO/Fe bilayers grown on a Ag(001)-stepped surface [18,20,21]. However, there are only a few reports regarding orthogonal coupling in the layered system with perpendicular magnetic anisotropy (PMA) [22][23][24].…”

Multiple in-plane spin reorientation transitions inFe/CoObilayers grown on vicinalMgO(001)

“…For NiO films grown on Ag(001) vicinal surfaces, the atomic steps could induce the in-plane uniaxial AFM anisotropy, and the NiO spins could be aligned either along or perpendicular to the steps direction depending 3 on the growth conditions [14]. The perpendicular coupling between Fe and NiO spins was proven by independently measuring the properties of Fe and NiO layers [15,16].…”

Volume contribution of exchange-coupling-induced uniaxial anisotropy in Fe/CoO/MgO(001) system

“…This result clearly proves that the observed volume contribution is only related to the exchange coupling rather than the crystalline structure. If the volume contribution was determined by the crystalline structure, such as the atomic step on the substrate, 19 its EA would always align along a certain direction with respect to the sample geometry. However, in our experiment, we found that the EA of volume uniaxial anisotropy was always perpendicular to the cooling field direction; therefore, we attribute the volume contribution to the CoO AFM ordering.…”

“…In order to explain the exchange-coupling-induced anisotropies, different mechanisms have been proposed, such as collinear coupling at the spin-uncompensated interface, 2 non-collinear (spin-flop) coupling 12 originating from spin frustration, 13 etc. Usually, such exchange-coupling-induced anisotropy is attributed to the interaction between FM spins and AFM spins at the interface, and the importance of interfacial spin coupling has been realized and well-studied in many FM/AFM systems, such as Fe/CoO, [14][15][16] Fe/NiO, [17][18][19] and Co/FeMn. 20,21 However, discussions on the anisotropy are mostly based on the measurement of the coercivity field H C , which is also proportional to 1/d FM .…”