Self-assembled single-crystal ferromagnetic iron nanowires formed by decomposition

Abstract

Arrays of perpendicular ferromagnetic nanowires have recently attracted considerable interest for their potential use in many areas of advanced nanotechnology. We report a simple approach to create self-assembled nanowires of alpha-Fe through the decomposition of a suitably chosen perovskite. We illustrate the principle behind this approach using the reaction 2La(0.5)Sr(0.5)FeO(3) --> LaSrFeO(4) + Fe + O(2) that occurs during the deposition of La(0.5)Sr(0.5)FeO(3) under reducing conditions. This leads to the spontaneous formation of an array of single-crystalline alpha-Fe nanowires embedded in LaSrFeO(4) matrix, which grow perpendicular to the substrate and span the entire film thickness. The diameter and spacing of the nanowires are controlled directly by deposition temperature. The nanowires show uniaxial anisotropy normal to the film plane and magnetization close to that of bulk alpha-Fe. The high magnetization and sizable coercivity of the nanowires make them desirable for high-density data storage and other magnetic-device applications.

A Novel, Layered Phase in Ti‐Rich SrTiO3 Epitaxial Thin Films

“…and exotic composite properties. [ 4,7,9 ] Researchers have demonstrated the ability to control the geometry, shape, and size of such phase-separated structures by tuning material composition, [ 10 ] growth temperature, [ 11 ] strain state, [ 12 ] growth, and cooling rates. [ 3,[13][14][15][16][17] Deterministic and ordered materials self-assembly in these systems is, however, a challenge.…”

Nanofabrication by advanced electron microscopy using intense and focused beam∗

“…It is expected that thermally stable Fe(CO) 5 molecules are not adsorbed on the surface. The Fe(CO) 4 compound is only formed when a ligand is lost from the molecule by electron impact, and is thermally disproportionate at temperatures above 423 K. Thus, Fe atoms are deposited close to the molecular decay sites initiated by electron-beam irradiation. The continuous supply of Fe atoms then promoted further nuclei growth in the long-axis direction.…”

“…One approach to the [3,4]. However, it is generally difficult to selectively grow nanoparticles at desired local positions.…”

Microstructural effects of chemical island templating in patterned matrix-pillar oxide nanocomposites

“…By selecting suitable complex oxides, a wide variety of functionalities can be achieved, such as multiferroic properties with a ferroelectric matrix and ferromagnetic pillar [3][4][5][6] , magneto-optical properties through a photostrictive matrix and magnetoelastic pillar 7 , or a metallic Fe nanowire embedded in anti-ferromagnetic LaSrFeO4 matrix, which has potential for magnetic exchange bias. 8 Novel functionalities in a wide variety of epitaxial nanocomposites is often observed due to the misfit strain between the matrix and pillar. 9 These epitaxial composites, also referred to as vertically-aligned nanocomposites, typically form through spontaneous self-assembly during film growth, which is the result of immiscibility between the two material systems.…”