ABSTRACT
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 Co3 O4 /Pd superlattices during irradiation. Structural investigations corroborate that progressive reduction of Co3 O4 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.
ABSTRACT
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.
ABSTRACT
1 T phase incorporation into 2H-MoS2 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 MoS2 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 MoS2 surface provides suitable ways for the low-dimensional device applications.
ABSTRACT
A bulk d0 NaN of rocksalt or zinc-blende structure was predicted to be a ferromagnetic half metal and furthermore the half-metallicity would be retained in thin films. Such half metallicity of d0 ferromagnetic NaN is attractive for possible application in a spintronics device, such as a spin transfer torque magnetic random access memory. In this study, we carried out first-principles calculations on magnetocrystalline anisotropy rocksalt structured NaN thin films with different thicknesses, using Vienna Ab-initio Simulation Package code. It was found that the NaN(001) thin films have perpendicular magnetization with quite low magnetocrystalline anisotropy energies of order of 10 µeV, but capping of a 5d-transition metal Ta monolayer over the NaN(001) thin films enhances the perpendicular magnetocrystalline anisotropy energies significantly, more than 10 times. Furthermore, the 1 (Ta)/NaN(001) systems retain their half-metallicity except the NaN layer just below Ta.