Impact of Annealing on Perpendicular Magnetic Anisotropy in W/MgAl2O4/CoFeMnSi/W/CoFeMnSi/MgAl2O4/W. Double Storage Layers for Upcoming MTJs

TL;DR

This study demonstrates how annealing temperature influences the perpendicular magnetic anisotropy in a multilayer heterostructure, highlighting the importance of interfacial oxidation control for spintronic device stability.

Contribution

It reveals the relationship between annealing temperature, interfacial oxidation, and magnetic anisotropy in CoFeMnSi/MgAl2O4 multilayers, proposing a method to enhance thermal stability of spintronic devices.

Findings

Maximum Keff achieved was 1.604 x 10^6 erg/cc at optimal annealing.

Interfacial oxidation significantly affects PMA strength.

Surface morphology and grain size are influenced by annealing temperature.

Abstract

In this study, we achieved the improvement of uniaxial perpendicular magnetic anisotropy (PMA) in the W/MgAl2O4/CoFeMnSi/W/CoFeMnSi/MgAl2O4/W heterostructure by manipulating the annealing temperature (TA) [350 C, 450 C, and 550 C]. We observed a maximum effective PMA energy density (Keff) of = 1.604 x 106 erg/cc with low saturation magnetization (Ms) at the specified TA. The enhancement of Keff with Ms is significantly influenced by structural variations at the interfaces of CoFeMnSi and MgAl2O4, attributed to sufficient interfacial oxidation dependent on the TA. The TA was identified as a critical factor affecting the surface morphology, grain size, and surface roughness of the multilayer. Fourier-transform infrared (FT-IR) measurements were employed to confirm the presence of Co-O or Fe-O bond in the multilayer structures, elucidating the true origin of PMA. The control of interfacial oxidation at the interface during annealing is crucial for regulating the strength of PMA. Therefore, this double CoFeMnSi/MgAl2O4-based multilayer presents a promising avenue, serving as a favorable candidate for future p-MTJs-based spintronic devices with enhanced thermal stability.