اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدInterdiffusion in epitaxial ultrathin Co2FeAl/MgO heterostructures with interface-induced perpendicular magnetic anisotropy
88
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The structures of epitaxial ultrathin Co2FeAl/MgO(001) heterostructures relating to the interface-induced perpendicular magnetic anisotropy (PMA) were investigated using scanning transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray magnetic circular dichroism. We found that Al atoms from the Co2FeAl layer significantly interdiffuse into MgO, forming an Al-deficient Co-Fe-Al/Mg-Al-O structure near the Co2FeAl/MgO interface. This atomic replacement may play an additional role for enhancing PMA, which is consistent with the observed large perpendicular orbital magnetic moments of Fe atoms at the interface. This work suggests that control of interdiffusion at ferromanget/barrier interfaces is critical for designing an interface-induced PMA system.
قيم البحث
اقرأ أيضاً
We investigated perpendicular magnetic anisotropy (PMA) and related properties of epitaxial Fe (0.7 nm)/MgAl2O4(001) heterostructures prepared by electron-beam evaporation. Using an optimized structure, we obtained a large PMA energy ~1 MJ/m3 at room
temperature, comparable to that in ultrathin-Fe/MgO(001) heterostructures. Both the PMA energy and saturation magnetization show weak temperature dependence, ensuring wide working temperature in application. The effective magnetic damping constant of the 0.7 nm Fe layer was ~0.02 using time-resolved magneto-optical Kerr effect. This study demonstrates capability of the Fe/MgAl2O4 heterostructure for perpendicular magnetic tunnel junctions, as well as a good agreement with theoretical predictions.
Using first-principles calculations, we investigated the impact of chromium (Cr) and vanadium (V) impurities on the magnetic anisotropy and spin polarization in Fe/MgO magnetic tunnel junctions. It is demonstrated using layer resolved anisotropy calc
ulation technique, that while the impurity near the interface has a drastic effect in decreasing the perpendicular magnetic anisotropy (PMA), its position within the bulk allows maintaining high surface PMA. Moreover, the effective magnetic anisotropy has a strong tendency to go from in-plane to out-of-plane character as a function of Cr and V concentration favoring out-of-plane magnetization direction for ~1.5 nm thick Fe layers at impurity concentrations above 20 %. At the same time, spin polarization is not affected and even enhanced in most situations favoring an increase of tunnel magnetoresistance (TMR) values.
Graphene is attractive for spintronics due to its long spin life time and high mobility. So far only thick and polycrystalline slabs have been used as ferromagnetic electrodes. We report the growth of flat, epitaxial ultrathin Co films on graphene. T
hese display perpendicular magnetic anisotropy in the thickness range 0.5-1nm, which is confirmed by theory. PMA, epitaxy and ultrathin thickness bring new perspectives for graphene-based spintronic devices such as the zero-field control of an arbitrary magnetization direction, band matching between electrodes and graphene, and interface effects such as Rashba and electric field control of magnetism.
Recently, perpendicular magnetic anisotropy (PMA) and its voltage control (VC) was demonstrated for Cr/Fe/MgO (Physical Review Applied 5, 044006 (2016)). In this study, we shed a light on the origin of large voltage-induced anisotropy change in Cr/Fe
/MgO. Analysis of the chemical structure of Cr/Fe/MgO revealed the existence of Cr atoms in the proximity of the Fe/MgO interface, which can affect both magnetic anisotropy (MA) and its VC. We showed that PMA and its VC can be enhanced by controlled Cr doping at the Fe/MgO interface. For Cr/Fe (5.9 {AA})/Cr (0.7 {AA})/MgO with an effective PMA of 0.8 MJ/m3, a maximum value of the voltage-controlled magnetic anisotropy (VCMA) effect of 370 fJ/Vm was demonstrated.
We investigated electronic structure and magnetic anisotropy in the Fe/MgO interface of magnetic metal and dielectric insulator under the Cr layer of small electronegativity, by means of the first-principles density functional approach. The result in
dicates that the interface resonance state gets occupied unlike a typical rigid band picture as the number of Fe layers decreases, finding large perpendicular anisotropies in the oscillating behavior for thickness dependence. We discuss scenarios of the two dimensional van Hove singularity associated with flat band dispersions, and also the accuracies of anisotropy energy in comparison with the available experimental data.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
