Low-field switchable dynamic anisotropy in FeCoN thin film with weak stripe domain

Y P Wu,Yong Yang,Jun Ding,Baoyu Zong,Z H Yang

doi:10.1063/1.4973761

Abstract

In this work, the static and dynamic magnetic properties of FeCoN films with various thickness have been studied. By controlling the deposition conditions, two-fold static anisotropies, namely a perpendicular anisotropy and an in-plane anisotropy, are introduced into the films, forming weak stripe domain. It is found that, for the films with the thickness between 130 nm and 240 nm, the anisotropy of FMR response is switchable. More importantly, the switching field of the dynamic anisotropy is only about 40-50 Oe, which is far below the value required to switch traditional rotatable anisotropy. Combined with high magnetic permeability and low-field switchable anisotropy, these films are promising for practical applications in the microwave devices.

Highlights

In recent decades, due to strong ferromagnetic resonance (FMR) at microwave range, ferromagnetic thin films with uniaxial in-plane anisotropy have attracted considerable interest for promising applications in magnetic devices.[1,2,3,4] the main critical constriction of the in-plane anisotropic film is that the permeability is highly directional-dependent
The permeability is decreased dramatically when the activation field deviates from the hard axis and drops to 1 along the easy axis.[5]
The parallel stripe domains are observed by Magnetic force microscopy (MFM) imaging for the films with thickness larger than 130 nm, while no obvious domain structure present in the films below the thickness (Figure 1)

Summary

Introduction

Due to strong ferromagnetic resonance (FMR) at microwave range, ferromagnetic thin films with uniaxial in-plane anisotropy have attracted considerable interest for promising applications in magnetic devices.[1,2,3,4] the main critical constriction of the in-plane anisotropic film is that the permeability is highly directional-dependent. High permeability can only be achieved along the hard axis (perpendicular to the magnetic moment). The permeability is decreased dramatically when the activation field deviates from the hard axis and drops to 1 along the easy axis.[5] the easy axis and hard axis are fixed and unable to change after film deposition. This leads to the great limitation to the practical applications which requires angularly tunable and controllable permeability

Methods

Results

Conclusion