Tunable magnetic properties of arrays of Fe(110) nanowires grown on kinetically-grooved W(110) self-organized templates

TL;DR

This study investigates the magnetic properties of self-organized Fe(110) nanowires on kinetically-grooved W(110) templates, demonstrating tunable magnetic anisotropy and blocking temperature through interface engineering.

Contribution

It introduces a new self-organized nanowire system with tunable magnetic properties and analyzes the effects of capping and underlayers on magnetic anisotropy.

Findings

Magnetic anisotropy varies with interface element and layer structure.

Blocking temperature of wires can be tuned from 50K to 200K.

Significant differences from flat film behavior are explained by step and strain effects.

Abstract

We report a detailed magnetic study of a new type of self-organized nanowires disclosed briefly previously [B. Borca et al., Appl. Phys. Lett. 90, 142507 (2007)]. The templates, prepared on sapphire wafers in a kinetically-limited regime, consist of uniaxially-grooved W(110) surfaces, with a lateral period here tuned to 15nm. Fe deposition leads to the formation of (110) 7 nm-wide wires located at the bottom of the grooves. The effect of capping layers (Mo, Pd, Au, Al) and underlayers (Mo, W) on the magnetic anisotropy of the wires was studied. Significant discrepancies with figures known for thin flat films are evidenced and discussed in terms of step anisotropy and strain-dependent surface anisotropy. Demagnetizing coeffcients of cylinders with a triangular isosceles cross-section have also been calculated, to estimate the contribution of dipolar anisotropy. Finally, the dependence of magnetic anisotropy with the interface element was used to tune the blocking temperature of the wires, here from 50K to 200 K.