Composition Dependence of Perpendicular Magnetic Anisotropy in Ta/Co_xFe_80-xB₂₀/MgO/Ta (x=0, 10, 60) Multilayers

Abstract

The perpendicular magnetic anisotropy of sputtered CoFeB thin films covered by MgO was investigated by vibrating sample magnetometry. Three different Co x Fe 80-x B 20 alloys were studied. Under out-of plane magnetic field, the saturation field was found to increase with increasing the Co content. The magnetization and interface anisotropy energy were obtained for all samples. Both showed a marked dependence on the MgO overlayer thickness. In addition, their variations were found to be non-monotonous as a function of the Co concentration.

Strain Mediated in‐Plane Uniaxial Magnetic Anisotropy in Amorphous CoFeB Films Based on Structural Phase Transitions of BaTiO3 Single‐Crystal Substrates

“…Figure (b) shows typical magnetization curves for θ H = 0° and 90° acquired at 300 K. A saturation magnetization ( M s ) of 1260 emu cm −3 was observed, in good agreement with previously reported data . The saturation field ( H s ) was 60 Oe for θ H = 90°, indicating that the initial hard and easy‐axes of the CoFeB film were induced along the b and a‐axes of the BTO substrate, respectively.…”

Thickness-dependent magnetoelasticity and its effects on perpendicular magnetic anisotropy in Ta/CoFeB/MgO thin films

“…Alternatively or in addition, another possible mechanism for the observed thickness dependence is that the same interface electronic effect (i.e. Fe-3d/O 2p hybridization) 24,25 at the CoFeB|MgO interface responsible for the strong PMA in the thin annealed and partially crystallized CoFe(B) films [26][27][28][29][30][31][32] also contributes an interface-like term to the effective magnetoelasticity of the annealed samples.…”

“…To analyze this effect, we employ a generalization of the Néel model that explicitly takes into account the magnetoelastic contribution to the magnetic energy 32,33 :…”

Measurement of magnetization using domain compressibility in CoFeB films with perpendicular anisotropy

“…In all cases, annealing slightly increases the magnetization, confirming the previous reports. [22][23][24] The compositions leading to the highest magnetizations are Co 20 Fe 60 B 20 and Co 40 Fe 40 B 20 . Position of ternary alloys on the Slater-Pauling curve is not obvious, 25,26 but it seems that boron has little influence on the magnetic properties apart from a dilution effect.…”