Evolution of In-Plane Magnetic Anisotropy In Sputtered FeTaN/TaN/FeTaN Sandwich Films

TL;DR

This study investigates how the in-plane magnetic anisotropy in FeTaN/TaN/FeTaN sandwich films evolves with varying TaN interlayer thickness, revealing axis switching and biaxial anisotropy driven by interlayer coupling, stress, and interface effects.

Contribution

It provides new insights into the mechanisms influencing magnetic anisotropy evolution in sputtered FeTaN/TaN/FeTaN films, highlighting the roles of interlayer coupling, stress, and interface roughness.

Findings

Easy-hard axis switching observed with changing TaN thickness

Biaxial anisotropy appears at certain interlayer thicknesses

Magnetostatic and interface anisotropies are key factors

Abstract

FeTaN/TaN/FeTaN sandwich films, FeTaN/TaN and TaN/FeTaN bilayers were synthesized by using RF magnetron sputtering. The magnetic properties, crystalline structures, microstructures and surface morphologies of the as-deposited samples were characterized using angle-resolved M-H loop tracer, VSM, XRD, TEM, AES and AFM. An evolution of the in-plane anisotropy was observed with the changing thickness of the nonmagnetic TaN interlayer in the FeTaN/TaN/FeTaN sandwiches, such as the easy-hard axis switching and the appearing of biaxial anisotropy. It is ascribed to three possible mechanisms, which are interlayer magnetic coupling, stress, and interface roughness, respectively. Interlayer coupling and stress anisotropies may be the major reasons to cause the easy-hard axis switching in the sandwiches. Whereas, magnetostatic and interface anisotropies may be the major reasons to cause biaxial anisotropy in the sandwiches, in which magnetostatic anisotropy is the dominant one.