We have performed first-principles calculations to study the interfacial exchange coupling and magnetocrystalline anisotropy energy in a SmCo 5 /Sm 2 Co 17 multilayer model system. The phase of SmCo ...5 and Sm 2 Co 17 stacking along (0001) direction are structurally well matched. The atomic structure, including the alignment and the separation between layers, were firstly optimized. Then the non-collinear magnetic structures were calculated to explore the exchange coupling across the interface and the variation of magnetocrystalline anisotropy energy. We found that the inter-phase exchange coupling strength, rotating behavior and magnetocrystalline anisotropy strongly depend on the atomic thickness of the SmCo 5 and Sm 2 Co 17 phase.
A partial substitution such as Ce in SmCo 5 could be a brilliant way to improve the magnetic performance, because it will introduce strain in the structure and breaks the lattice symmetry in a way ...that enhances the contribution of the Co atoms to magnetocrystalline anisotropy. However, Ce substitutions, which are benefit to improve the magnetocrystalline anisotropy, are detrimental to enhance the Curie temperature ( T C ). With the requirements of wide operating temperature range of magnetic devices, it is important to quantitatively explore the relationship between the T C and ferromagnetic exchange energy. In this paper we show, based on mean-field approximation, artificial tensile strain in SmCo 5 induced by substitution leads to enhanced effective ferromagnetic exchange energy and T C , even though Ce atom itself reduces T C .
In atomic GdFe 2 films capped by 4d and 5d transition metals, we show that skyrmions with diameters smaller than 12 nm can emerge. The Dzyaloshinskii–Moriya interaction (DMI), exchange energy, and ...the magnetocrystalline anisotropy (MCA) energy were investigated based on density functional theory. Since DMI and MCA are caused by spin–orbit coupling (SOC), they are increased with 5d capping layers which exhibit strong SOC strength. We discover a skyrmion phase by using atomistic spin dynamic simulations at small magnetic fields of ∼1 T. In addition, a ground state that a spin spiral phase is remained even at zero magnetic field for both films with 4d and 5d capping layers.
Rh-terminated FeRh(001) film is known to be stable in a ferromagnetic (FM) state different from a G-type antiferromagnetic (G-AFM) bulk ground state, while an Fe-terminated FeRh(001) film has the ...same ground state as the bulk. In this paper, we investigate the magnetic properties of asymmetrically terminated FeRh(001) films: one surface is Fe-terminated and the other is Rh-terminated. We found that the films thicker than eight monolayers (MLs) have more or less complicated magnetic configuration: the topmost three layers from the Rh-terminated surface are FM while the rest are G-AFM. In particular, the magnetic configuration of the 8-ML FeRh(001) film has lower energy than the whole-layer G-AFM and FM states by 10.2 and 0.2 meV/Fe, respectively. The magnetic configuration of the asymmetrically terminated films is explained by the magnetic energy gain due to the magnetization of the Rh atoms.
We have performed first-principles calculations to study the interfacial exchange coupling and magnetocrystalline anisotropy energy in a SmCo 5 /Sm 2 Co 17 multilayer model system. The phase of SmCo ...5 and Sm 2 Co 17 stacking along (0001) direction are structurally well matched. The atomic structure, including the alignment and the separation between layers, were firstly optimized. Then the non-collinear magnetic structures were calculated to explore the exchange coupling across the interface and the variation of magnetocrystalline anisotropy energy. We found that the inter-phase exchange coupling strength, rotating behavior and magnetocrystalline anisotropy strongly depend on the atomic thickness of the SmCo 5 and Sm 2 Co 17 phase.
Orbital anisotropy at interfaces in magnetic heterostructures has been key to pioneering spin–orbit‐related phenomena. However, modulating the interface's electronic structure to make it abnormally ...asymmetric has been challenging because of lack of appropriate methods. Here, the authors report that low‐energy proton irradiation achieves a strong level of inversion asymmetry and unusual strain at interfaces in Co/Pd superlattices through nondestructive, selective removal of oxygen from Co3O4/Pd superlattices during irradiation. Structural investigations corroborate that progressive reduction of Co3O4 into Co establishes pseudomorphic growth with sharp interfaces and atypically large tensile stress. The normal component of orbital to spin magnetic moment at the interface is the largest among those observed in layered Co systems, which is associated with giant orbital anisotropy theoretically confirmed, and resulting very large interfacial magnetic anisotropy is observed. All results attribute not only to giant orbital anisotropy but to enhanced interfacial spin–orbit coupling owing to the pseudomorphic nature at the interface. They are strongly supported by the observation of reversal of polarity of temperature‐dependent Anomalous Hall signal, a signature of Berry phase. This work suggests that establishing both giant orbital anisotropy and strong spin–orbit coupling at the interface is key to exploring spintronic devices with new functionalities.
The unique pseudomorphic interfacial structure of Co/Pd constructed by phase‐transformation of paramagnetic Co3O4/Pd to ferromagnetic Co/Pd superlattices by low‐energy proton irradiation makes it possible to induce extraordinarily large orbital anisotropy and strongly enhances spin–orbit coupling (SOC) at the interface, which can be attributed to the strong level of structural inversion asymmetry (SIA) and the substantial in‐plane tensile stress built up at the interface between Co and Pd.
The magnetism of FeRh (001) films strongly depends on film thickness and surface terminations. While the magnetic ground state of bulk FeRh is G-type antiferromagnetism, the Rh-terminated films ...exhibit ferromagnetism with strong perpendicular magnetocrystalline anisotropy whose energy +2.1 meV/whitesquare is two orders of magnitude greater than bulk 3d conventional magnetic metals (whitesquare is the area of a two-dimensional unit cell). While the Goodenough-Kanamori-Anderson rule on the superexchange interaction is crucial in determining the magnetic ground phases of FeRh bulk and thin films, the magnetic phases are the results of interplay and competition between three mechanisms-the superexchange interaction, the Zener-type direct interaction, and energy gain by Rh magnetization.
Abstract
1 T phase incorporation into 2H-MoS
2
via
an optimal electron irradiation leads to induce a weak ferromagnetic state at room temperature, together with the improved transport property. In ...addition to the 1T-like defects, the electron irradiation on the cleaved MoS
2
surface forms the concentric circle-type defects that are caused by the 2 H/1 T phase transition and the vacancies of the nearby S atoms of the Mo atoms. The electron irradiation-reduced bandgap is promising in vanishing the Schottky barrier to attaining spintronics device. The simple method to control and improve the magnetic and electrical properties on the MoS
2
surface provides suitable ways for the low-dimensional device applications.
1 T phase incorporation into 2H-MoS
via an optimal electron irradiation leads to induce a weak ferromagnetic state at room temperature, together with the improved transport property. In addition to ...the 1T-like defects, the electron irradiation on the cleaved MoS
surface forms the concentric circle-type defects that are caused by the 2 H/1 T phase transition and the vacancies of the nearby S atoms of the Mo atoms. The electron irradiation-reduced bandgap is promising in vanishing the Schottky barrier to attaining spintronics device. The simple method to control and improve the magnetic and electrical properties on the MoS
surface provides suitable ways for the low-dimensional device applications.
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