Magnetism and exchange-bias effect at the MnN/Fe interface

Abstract

Based on ab initio calculations and spin dynamics simulations, we perform a detailed study on the magnetic properties of bulk MnN and the MnN/Fe interface. We determine the spin model parameters for the θ-phase of bulk MnN, and we find that the competition between the nearest and the next-nearest-neighbor interactions leads to antiferromagnetic ordering of the Mn spins, in agreement with previous theoretical and experimental results. At the MnN/Fe interface, a sizable Dzyaloshinskii-Moriya interaction appears leading to a stable exchange-bias effect. We study the dependences of the exchange-bias effect on the thicknesses of the ferromagnetic and the antiferromagnetic layers, and we compare them to experimentally obtained results [Meinert et al., Phys. Rev. B 92, 144408 (2015)].

Thermal stability of exchange bias systems based on MnN

“…This decrease is possibly due to desorption of nitrogen from the MnN [16] or an irreversible structural/magnetic transition in the MnN or at the MnN/CoFe interface [7]. The shape of the hysteresis loops as well as the magnitude of the loop shift are in good agreement with recent theoretical investigations by Simon et al [17], albeit for a different ferromagnetic system. As can be seen in Figure 2 the Mn spins in the MnN layer are oriented out-of-plane.…”

“…At the interface between the F and AF layers there is ferromagnetic coupling with the spins preferring to lie in a direction parallel to the plane of the interface. This leads to a twisted spin structure across the interface [17]. The value of the anisotropy constant varied from sample to sample which is shown in the data in Figure 8 due to the proportionality of <TB>, i.e.…”

Tuning Ferromagnetism in a Single Layer of Fe above Room Temperature

“…The Curie temperature for ferromagnetic ground states was obtained from the magnetization curve M 2 (T) resulting from finite temperature atomistic spin-dynamics simulations [22], a recent example using this method is reported in Ref. [23].…”

“…Materials 2022, 15, x FOR PEER REVIEW 4 of 14 atomistic spin-dynamics simulations [22], a recent example using this method is reported in Ref. [23].…”

Recent Developments on MnN for Spintronic Applications

“…In both cases, the Mn atoms had a magnetic moment of 3.3 µ B at room temperature. More recently, a theoretical study has suggested that the spin alignment is along the c-axis [16]. The authors found that the first nearest-neighbor isotropic exchange interactions are AF, while the second nearest-neighbor interactions are strongly ferromagnetic.…”